A software engineer at a company that replaces computers in schools with termina

Question

A software engineer at a company that replaces computers in schools with terminals connected to a server is testing a new server to see if mean download times are decreased with the new server. When he compares a random sample of 20 times to the previous standard he gets a t-statistic of -17.

a). Explain what the t-statistic means in this context. Choose the correct answer below.
A. The mean download time is 17 standard errors above the hypothesized mean.
B. The new mean download time is 17 times greater than the previous mean download time.
C. The new mean download time is 1/17 the previous mean download time.
D. The mean download time is 17 minutes.
E. The mean download time is 17 standard errors below the hypothesized mean.

b) Find the 0.001 lower critical value for a t-statistic with 19 df and state the conclusion about the test.
The critical value is
(Round to three decimal places as needed.)

c) What is the proper conclusion to this test?
A. Reject the null hypothesis. There is insufficient evidence to conclude that the mean download times have decreased. B. Reject the null hypothesis. There is sufficient evidence to conclude that the mean download times have decreased.
C. Fail to reject the null hypothesis. There is insufficient evidence to conclude that the mean download times have decreased.
D. Fail to reject the null hypothesis. There is sufficient evidence to conclude that the mean download times have decreased.

Question b) is what I need assistance understanding. It says in my book to use "technology" to find the answer but doesn't tell me what to use. Please help.

Explanation / Answer

A software engineer at a company that replaces computers in schools with terminals connected to a server is testing a new server to see if mean download times are decreased with the new server. When he compares a random sample of 20 times to the previous standard he gets a t-statistic of -17.

The hypothesis for the test is,

H0 : mu = mu0 Vs H1 : mu < mu0

a). Explain what the t-statistic means in this context. Choose the correct answer below.

E. The mean download time is 17 standard errors below the hypothesized mean.

b) Find the 0.001 lower critical value for a t-statistic with 19 df and state the conclusion about the test.

It means probability is 0.001 and

df = 19

The critical value we can find by using EXCEL(technology).

syntax :

=TINV(probability, deg_freedom)

Critical value = 3.883

c) What is the proper conclusion to this test?

| t | = 17

| t | > critical value

B. Reject the null hypothesis. There is sufficient evidence to conclude that the mean download times have decreased.

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