A sensationseeking questionnaire is developed by Evilck and

A sensation-seeking questionnaire is developed by Evilck and Eville (1978). With this questionnaire it is found that the general population of 10 year-old boys has a mean of ? = 15.4. Sylvester and Tweety (1995) were interested in testing whether 10 year-old boys who had been exposed to violent cartoons tend to differ from the general population on sensation-seeking.
These researchers obtained a sample of 15 boys who had been exposed to violent cartoons on a regular basis. The boys\' scores on the questionnaire were:
21, 10, 16, 20, 14, 21, 22, 11, 23, 15, 14, 14, 13, 21, 13

C. What is the appropriate conclusion? (Please choose ALL answers necessary to draw a complete conclusion)

True False  Fail to reject the null hypothesis.
True False  Accept the alternative hypothesis.
True False  There is no evidence that watching violent cartoons has a statistically significant effect on sensation-seeking scores.
True False  Reject the null hypothesis.
True False  Watching violent cartoons appears to raise sensation-seeking scores.

Solution

sample mean=16.53333

sample standard deviation=4.340287

Let mu be the population mean

The test hypothesis:

Ho: mu=15.4 (i.e. null hypothesis)

Ha: mu not equal to 15.4 (i.e. alternative hypothesis)

The test statisitc is

t=(xbar-mu)/(s/vn)

=(16.53333-15.4)/(4.340287/sqrt(15))

=1.01

The degree of freedom =n-1=15-1=14

Assume that the significant level a=0.05

It is a two-tailed test.

The critical values are t(0.025, df=14) =2.14 or -2.14 (from student t table)

The rejection regions are if t<-2.14 or t>2.14, we reject the null hypothesis.

Since t=1.01 is between -2.14 and 2.14, we do not reject the null hypothesis.

Answer:

True False  Fail to reject the null hypothesis.
True False  Accept the alternative hypothesis.
True False  There is no evidence that watching violent cartoons has a statistically significant effect on sensation-seeking scores.
True False  Reject the null hypothesis.
True False Watching violent cartoons appears to raise sensation-seeking scores.