Question

The data entry operation in a large computer department claims that it gives its customers a turn around time of 10 hours on average. The National Consumer Agency acting on behalf of customers analyses a random sample of jobs recently completed by the department and produces the following output using SPSS :

One-Sample Statistics

N Mean Std. Deviation Std. Error MeanTime

Time 14 10.32 1.70 (i)

One-Sample Test

Test Value = 10

95% Confidence Interval of the Difference

t df Sig. (2-tailed) Mean Difference Lower Upper

Time (ii) (iii) 0.4937 0.32 -0.618 1.258

Which of the following sets of hypotheses are being tested in Table 2?

a : H 0: μ = 10 hours

  H a: μ < 10 hours

b : H 0: μ = 10 hours

H a: μ > 10 hours

c : H 0: μ = 10 hours

  H a: μ ≠ 10 hours

Insert your choice (a, b or c): .

Fill in the three missing values in the output (i)-(iii).

(i) = (2 dec places)

(ii) = (2 dec places)

(iii) =

Use the output to help you complete the test, testing at significance level α = 0.05 , by filling in the blanks in the following:

The P-value for this test is (as printed) .

Since the P-value is _________(smaller/larger) than____________ (2 dec places), there (is evidence/is no evidence) to reject the null hypothesis, H0.

There (is sufficient/is insufficient) evidence to suggest that the true average time it takes to complete data entry jobs, μ, is different to 10 hours.

Were any assumptions required in order for this inference to be valid?

a: No - the Central Limit Theorem applies, which states the sampling distribution is normal for any population distribution.

b: Yes - the population distribution must be normally distributed. Insert your choice (a or b): .

Answer 1

To test against

The value of the test statistic = 0.4937

P-value for this test = 0.32

Since the P-value is larger than 0.05, there is no evidence to reject the null hypothesis, H0.

There is insufficient evidence to suggest that the true average time it takes to complete data entry jobs, μ, is different to 10 hours.

Assumptions required in order for this inference to be valid :

ans-> b: Yes - the population distribution must be normally distributed.