35. Mutual Fund Performance. Business Insider reported that 58% of mutual funds underperformed in 2013, against the Standard and Poor 500 benchmark. Suppose a random sample of 100 mutual funds showed 67 that had underperformed. Test whether the population proportion has increased, using level of significance .
9.5.35
Both and , so the conditions for using the test for proportions are met.
Step 1
We reject if the .
Step 2
Step 3
Step 4 The is , so we reject . There is evidence at level of significance that the population proportion of mutual funds that underperform has increased from 58%.