1. 55people are randomly selected and the accuracy of their wristwatches is checked, with positive errors representing watches that are ahead of the correct time and negative errors representing watches that are behind the correct time. The55values have a mean of30sec and a standard deviation of178sec. Use a0.01significance level to test the claim that the population of all watches has a mean of0sec. (Assume?=178sec.)

(a) The test statistic =

(b) TheP- value =

(c) The final conclusion is

A.The results are statistically significant. There is evidence that the mean is not equal to 0.

B. The results are not statistically significant. There is insufficient evidence to claim that the mean is not equal to 0.

2. Jen thinks a certain potato chip maker is putting fewer chips in their regular bags of chips. From a random sample of 11 bags of potato chips she calculated aPvalue of 0.124 for the sample.

(a) At a 5% level of significance, is there evidence that Jen is correct?

(b) At a 10% level of significance, is there evidence that she is correct?

(c) In a statistical test of hypotheses, we say that the data are statistically significant at level?if

A. theP- value is larger than?.

B.?is small.

C.?=0.05.

D. theP- value is less than?.

3. The P-value for a two sided test of the null hypothesis

H0:?=12is 0.064.(a) Does the 95% confidence interval include the value of12?

(b) Does the 90% confidence interval include the value of12?