Question

In a study of computer use, 1000 randomly selected Canadian Internet users were asked how much time they spend using the Internet in a typical week. The mean of the sample observations was 12.6 hours.

(a)

The sample standard deviation was not reported, but suppose that it was 4 hours. Carry out a hypothesis test with a significance level of 0.05 to decide if there is convincing evidence that the mean time spent using the Internet by Canadians is greater than 12.4 hours. (Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)

t= 1.58

P-value= .057

State the conclusion in the problem context.

Do not reject H₀. We do not have convincing evidence that the mean weekly time spent using the Internet by Canadians is greater than 12.4 hours.

Now suppose that the sample standard deviation was 3 hours. Carry out a hypothesis test with a significance level of 0.05 to decide if there is convincing evidence that the mean time spent using the Internet by Canadians is greater than 12.4 hours. (Use a statistical computer package to calculate the P-value. Round your test statistic to two decimal places and your P-value to three decimal places.)

t=

P-value=

Answer 1

Ans a 0 using excel>addin>phstat>one sample test

we have

t Test for Hypothesis of the Mean
Data
Null Hypothesis                m=	12.4
Level of Significance	0.05
Sample Size	1000
Sample Mean	12.6
Sample Standard Deviation	4
Intermediate Calculations
Standard Error of the Mean	0.1265
Degrees of Freedom	999
t Test Statistic	1.5811
Upper-Tail Test
Upper Critical Value	1.6464
p-Value	0.0571
Do not reject the null hypothesis

t= 1.58

P-value= .057

Do not reject H0. We do not have convincing evidence that the mean weekly time spent using the Internet by Canadians is greater than 12.4 hours.

Ans b )

t Test for Hypothesis of the Mean
Data
Null Hypothesis                m=	12.4
Level of Significance	0.05
Sample Size	1000
Sample Mean	12.6
Sample Standard Deviation	3
Intermediate Calculations
Standard Error of the Mean	0.0949
Degrees of Freedom	999
t Test Statistic	2.1082
Upper-Tail Test
Upper Critical Value	1.6464
p-Value	0.0176
Reject the null hypothesis

t= 2.11

P-value= .018

reject H0. We have convincing evidence that the mean weekly time spent using the Internet by Canadians is greater than 12.4 hours.