Question

According to most estimates, 10% of the people in the general population are left-handed and 90% are right-handed. A neurological theory of handedness and cerebral dominance predicts that there should be a disproportionate number of left-handers among artists. For a sample of n = 150 artists, a psychologist finds that 24 are left-handed. Is there a higher proportion of left-handers among artist than there is for the general population? Test with alpha set at .05. For full points indicate in the box below, 1) null hypothesis, 2) z, 3) fail or fail to reject null hypothesis, and 4) interpretation or conclusion.

Answer 1

Here, 10% of the people in the general population are left-handed. We want to test whether this proportion is higher for artists. To test:

H0 : p = 0.10

H1 : p > 0.10

The sample proportion , = 24/150

= 0.16

n = 150

The test statistic , z = ( - p) / [p(1-p)/n]

= 0.06 / 0.0245

= 2.45

At alpha= 0.05 , z(critical) = 1.645

Therefore, z(Critical) > z

We reject the null hypothesis at alpha =0.05 when the critical value is greater than the test statistic.

Therefore, we conclude that the proportion of left handers is higher for artists.