# Chapter 1. Matched Pairs and Other Block Designs

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Stat Tutor
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2:03

### Question 1.1

Incorrect. A block is a group of individuals that are similar with respect to some characteristic known before the experiment begins.
Correct. A block is a group of individuals that are similar with respect to some characteristic known before the experiment begins.
Incorrect. Try again.
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### Question 1.2

Incorrect. In a randomized block design, the random assignment of individuals to treatments is done within each block. So a different randomization is done in every block.
Correct. In a randomized block design, the random assignment of individuals to treatments is done within each block. So a different randomization is done in every block.
Incorrect. Try again.
2

### Question 1.3

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Incorrect. In both a stratified sample and a randomized block design, the individuals are grouped before the study begins. In a stratified sample, the groups are called strata and the individuals are randomly selected from every stratum; in a randomized block design, the groups are called blocks and individuals are randomly allocated to treatments within each block. While the studies are similar, the terms "stratified sample" and "block design" are never interchanged.
Correct. In both a stratified sample and a randomized block design, the individuals are grouped before the study begins. In a stratified sample, the groups are called strata and the individuals are randomly selected from every stratum; in a randomized block design, the groups are called blocks and individuals are randomly allocated to treatments within each block. While the studies are similar, the terms "stratified sample" and "block design" are never interchanged.
Incorrect. Try again.
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4:28

### Question 1.4

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Incorrect. These rats vary by size, breed and length.
Correct. These rats vary by size, breed and length.
Incorrect. Try again.
2

### Question 1.5

SRUciCohvS/LnzAcYufDR9pA3rXLziWhrWW237WpXvSd0jdc5q1XiXDHbqrONl1E5T6HvsnLEZYGyjofW5aKYTVCnvczs68k
Incorrect. Certainly the bigger rats ought to be able to complete the maze faster than smaller rats.
Correct. Certainly the bigger rats ought to be able to complete the maze faster than smaller rats.
Incorrect. Try again.
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5:23

### Question 1.6

Incorrect. Whenever individuals are similar with respect to some characteristic and that characteristic is expected to affect the response, blocks should be used.
Correct. Whenever individuals are similar with respect to some characteristic and that characteristic is expected to affect the response, blocks should be used.
Incorrect. Try again.
2

### Question 1.7

Incorrect. With this randomized block design, rats should be randomly assigned to drugs within each litter.
Correct. With this randomized block design, rats should be randomly assigned to drugs within each litter.
Incorrect. Try again.
2

6:11

### Question 1.8

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Incorrect. Control/comparison requires either a control versus an active treatment group OR two or more active treatment groups or both. In this experiment, five active treatments (five drugs) will be compared so it has comparison.
Correct. Control/comparison requires either a control versus an active treatment group OR two or more active treatment groups or both. In this experiment, five active treatments (five drugs) will be compared so it has comparison.
Incorrect. Try again.
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6:16

### Question 1.9

o/K/nVYtCTIFdymaUqB+BC5CDVhuW69h7dXg2RYFDmh3PhSV1oBhrK93qpe10WcmrNOYHM6gDMp+KAW5INgCSCe1jZQWPvhtm8UhD44WschP7aTRLfX+VFt2sE89GVllO1zS555kTBWAMNpAkrLBOdNrS6iVT8IjT27rhyx/lvYB+/GozWMcOcVdwP13wCl2
Incorrect. Randomly assigning rats to drugs is what is meant by randomization in an experiment.
Correct. Randomly assigning rats to drugs is what is meant by randomization in an experiment.
Incorrect. Try again.
2

6:24

### Question 1.10

q35kdM2trLf7PZwoiMBxRmLQVXJi3gDxeKYcMgwfMJYEiL31kZpHI+IDFoAjxV3paX7aOR+UWBP2B6TyGEV5SUrkjoUnwiJZpReWxhYrABZ2PYlh3+VMt91LDjbXpyJAiC5RJA+nJZYyvXzwk9HOPN+ycA0igv3xVVCXvlLxITWFQHeb4eq1TwD2DW4WLAu2jZ2dkyH29DfjjpcozSaJ4w==
Incorrect. We recognize an experiment as being a randomized block design when the randomization is carried out within each group.
Correct. We recognize an experiment as being a randomized block design when the randomization is carried out within each group.
Incorrect. Try again.
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### Question 1.11

Incorrect. Since there are six litters and one rat in each litter gets each drug, six rats receive each drug. So, the replication is the six rats receiving each drug.
Correct. Since there are six litters and one rat in each litter gets each drug, six rats receive each drug. So, the replication is the six rats receiving each drug.
Incorrect. Try again.
2

6:36

### Question 1.12

K76VJZpgMBvUa9bPXh/upRmJXkKc1cYfqipyuKlhZTtMQ/uNPfPOC4ziiifC74nIEJV/8fPacrPQ7+uBXwJnV2xfRvKobvq7zapgn+EIFdKViNfy9QyA11m3BL6zwXWz3ULpN6wy/uhxz4yO2M2la+mHcu3lVql5IeH32eeAedvR8pH4Cm6UVsQvKn3ba/ZYQ0W1uzSjqErKh6RkALPQHF8x/IAf/QlYAPiEYQ==
Incorrect. In a randomized block design, randomization is carried out within each block whereas for a completely randomized design, randomization is carried out for all individuals available for the experiment.
Correct. In a randomized block design, randomization is carried out within each block whereas for a completely randomized design, randomization is carried out for all individuals available for the experiment.
Incorrect. Try again.
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7:39

### Question 1.13

UqlemX6giQt8Qe9XquTLI7vRJkDY88hsR/QDxasd3J1wdkuFZyzPcl58+kfS2T3PVZOtHoFSwy87RH4tmKIrTWGSTcGmso0ZPx2KVVTthJk8pVaT/A4VuMjga6Au/21X8RN+D2cbHBO3im8KIJxYSmsHlR7V8cxKWLA3RndyDRFB5PdR9WQoDdNZYRMJvkGu3gktn3gnBeSwscG7iGB5OE3ThO148dIYvvfdiFaV67HmHG9sWnI0+az6oiPmkHV3lSGeQtkBTXoWHU18y1ny/13Q5vof2sMigUybB7nFNQQb1ez15jcs4sW8b7J8XFqFOste47rkqd+vpN5PVBsf5wVO0B+54RSPxLyUVhHn7HLQT6Zi
Incorrect. Since the blue plot is much lower than all of the other plots, those rats completed the maze in lower times.
Correct. Since the blue plot is much lower than all of the other plots, those rats completed the maze in lower times.
Incorrect. Try again.
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9:15

### Question 1.14

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Incorrect. This is a correct statement.
Correct. This is a correct statement.
Incorrect. Try again.
2

### Question 1.15

0NLi1ClNAEu0hDlHESFBseOsCd/CvF0fxy9n7xP4gyXh5wxwUFJXRY8GaNMmCq4CqF36FmUJS/PrDHJKGayvccGGIJZ2M1NP4TO+IMVrM0XQlKVD5kvL7kQSCVosB6O5FUs+wEEpLrZ84BhHBvp3Pkh3Qu1ixMSmC3cUDaTvG07BHmvJh08c1Mz6PcuWzLZ9e9yi5ts7KPM=
Incorrect. In a matched pairs design, the blocks can be either paired individuals or paired measurements.
Correct. In a matched pairs design, the blocks can be either paired individuals or paired measurements.
Incorrect. Try again.
2

### Question 1.16

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Incorrect. When the pair consists of individuals, randomization must be carried out within the pair (block). So the individuals in each pair must be randomly allocated to the two treatments.
Correct. When the pair consists of individuals, randomization must be carried out within the pair (block). So the individuals in each pair must be randomly allocated to the two treatments.
Incorrect. Try again.
2

### Question 1.17

s+nBYIS1sHwd0Fkaj2Beql5PrdvBIniQNauuQo+Bg9M+j25zoimRPOZoi0YZlctDfnMp6ojqtKoRrR9E0mXjbUDdat+8Gg8JgIB0hKiwFuS08aE5C7cKnQauZmNGmh6aT8Uk+RSlJICW4BDFrvR119ahpFLrcotQygkyfkjdsnK8b+q6B6A+TYm9id0Fb3mtGgt2krgv6mPiPxs7tyeTVDv993VDpj3c5fejcbAoPo6ToY96y+uFJ7//DETgQk1CG8ebGfwwiDBT/wMgy8UUZL+HWLMCniXaUmjmH8OMonwIW0h5QdSgBH3U13PQBig6jFAHtg==
Incorrect. Since each pair (whether two individuals or two measurements) gets both treatments, the number of pairs is the replication.
Correct. Since each pair (whether two individuals or two measurements) gets both treatments, the number of pairs is the replication.
Incorrect. Try again.
2

### Question 1.18

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Incorrect. Remember, one of the treatments could be a control (placebo) treatment.
Correct. Remember, one of the treatments could be a control (placebo) treatment.
Incorrect. Try again.
2

9:58

### Question 1.19

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Incorrect. Each set of identical twins is a pair of matched individuals.
Correct. Each set of identical twins is a pair of matched individuals.
Incorrect. Try again.
2

### Question 1.20

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Incorrect. In a randomized block design, randomization is carried out within each block. In a matched pairs experiment, a block is a pair so the randomization must be carried out within each pair.
Correct. In a randomized block design, randomization is carried out within each block. In a matched pairs experiment, a block is a pair so the randomization must be carried out within each pair.
Incorrect. Try again.
2

10:59

### Question 1.21

OY32ZVAByXIi0CilfKPCt1tHIIGWFnBKWCY36sQ5jyCQLv9L8aQUzDd2Ja2W3BjRbWoZhIkcn5e4HyLgiQkjl4cARoxw+R6Ccycqrmgtcq9p/bKwwxzhrz3qbnpZZm+hEBtCyJr4YeISgc1RDYAs8vca6GJJSpCc/NctPRS3v53gjKuAtLorNt0zz9AkqTr6Cu0+DGYcGMztjvagFax5jzw04HwLVGPJvhZzhYMNNtuTKyR81SZxRxHfgoAuLPQHiR2v4VBBUwg4MU0ZZQ7OcNszSyGUDSu5b6wtZgDem3Psikj1xVYLP/mqW1vjO/qmL44uP6dKgdi5lQgSd/t7ZijuojFe3G1HVP1X35yO2mXkd48YX+qJAU+FxY/FE9SgVnZPT2YgE6o=
Incorrect. In a matched pairs design, the blocks can be either paired individuals or paired measurements. In this experiment, each subject receives both treatments (colas), so the measurements are paired.
Correct. In a matched pairs design, the blocks can be either paired individuals or paired measurements. In this experiment, each subject receives both treatments (colas), so the measurements are paired.
Incorrect. Try again.
2

### Question 1.22

Incorrect. Since this matched pairs experiment has two measurements on each subject (one for each type of cola), the order in which each subject tastes each cola must be randomized.
Correct. Since this matched pairs experiment has two measurements on each subject (one for each type of cola), the order in which each subject tastes each cola must be randomized.
Incorrect. Try again.
2

11:30

### Question 1.23

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Incorrect. With a completely randomized design, all individuals are randomly allocated to the treatment groups.
Correct. With a completely randomized design, all individuals are randomly allocated to the treatment groups.
Incorrect. Try again.
2

12:17

### Question 1.24

Incorrect. With a completely randomized design, all individuals are randomly allocated to the treatment groups.
Correct. With a completely randomized design, all individuals are randomly allocated to the treatment groups.
Incorrect. Try again.
2

12:28

### Question 1.25

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Incorrect. The bigger rats will potentially gain more weight than the smaller rats.
Correct. The bigger rats will potentially gain more weight than the smaller rats.
Incorrect. Try again.
2

13:25

### Question 1.26

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Incorrect. One rat of each size could be in each diet group with several different random allocations. And you could get other completely randomized designs that have rats of different sizes in each diet group. But this is the only design that will randomly assign one rat from each litter to each diet group.
Correct. One rat of each size could be in each diet group with several different random allocations. And you could get other completely randomized designs that have rats of different sizes in each diet group. But this is the only design that will randomly assign one rat from each litter to each diet group.
Incorrect. Try again.
2

14:46

### Question 1.27

Incorrect. We should only perform a completely randomized design when the individuals are similar with respect to variables that might affect the response variable.
Correct. We should only perform a completely randomized design when the individuals are similar with respect to variables that might affect the response variable.
Incorrect. Try again.
2

### Question 1.28

KAbJjWmV4bPKLJHPlIqpfjBG/ya9yLxh3wTf4od7ydLKDs2HkesOxKY9TfiR/Tkd1BAsd0ZiBEh5l0Rmt7ahcA2PuPnVyPRcwBHjyzPMYAgzKIoA+EY/QP3Suf0WLgr82vz+iObCoqImGNaNlbe2RmV4mula1NMgajm6RRXAamgYzBdk7XnPLul2YB/XpBBEuHuUTJg5PUp5KBNf0xjetJI+mWGysoixeVwWr1Eo4+5/7IYPzBp0cN/D3Mdkguk4/RXeAS3dJoXXQo18J5NW+U8tUD9hlJjMbtq8vHaG0e2YS3Hs8VVvyZWCBFNG9/4tPzUgz1PqHcRzeCsB1klfT9uxEhVr51soJDcMDyy9hPelz71xDpRUf1ZznX+Aoz1nd8+UOm3qepeDY/NVMl4JHZkXO7iYXdnY+zNkwikbRBBiWOae6UVlU4n/7FSinAp+ZdTyng==
Incorrect. Whenever a group of individuals are similar with respect to some characteristic known before the study begins and when that characteristic is expected to affect the response variable, a randomized block design should be performed.
Correct. Whenever a group of individuals are similar with respect to some characteristic known before the study begins and when that characteristic is expected to affect the response variable, a randomized block design should be performed.
Incorrect. Try again.
2

15:33

### Question 1.29

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
Incorrect. A randomized block design reduces chance variation by removing the variation associated with the blocking variable. This gives a more precise estimate of chance variation. One further note: lurking variables cannot be eliminated, only dealt with. And in a true randomized block design, there is no interaction between the blocking variable and the explanatory variable.
Correct. A randomized block design reduces chance variation by removing the variation associated with the blocking variable. This gives a more precise estimate of chance variation. One further note: lurking variables cannot be eliminated, only dealt with. And in a true randomized block design, there is no interaction between the blocking variable and the explanatory variable.
Incorrect. Try again.
2