Statistic Help?

1. In 1998, Chips Ahoy announced an advertising campaign that their bag of cookies had more than 1000 chips. Some students counted the number of chips in the cookies. They found an average of 1024 chips with a standard deviation of 43 chips. They counted the number of chocolate chips in 20 bags. What is the test statistic?
Round your answer to two decimal places.



2.An employment information service claims that the mean annual pay for full time male workers over age 25 and without high school diplomas is $18,600.
You decide to test this claim - you think that that value is too low. You collect a random sample of 10 men over the age of 25 that do not have a high school diploma.
The test statistic is 0.57.

Which of these statements is true about the p-value?

a. The test statistic is not on the table; therefore, we can't find a p value.

b. the p-value is greater than 0.10

c. the p-value is 0.2157

d. the p-value is 0.2843

e. The p-value is less than 0.10

1) This would be tested with a paired t-test.
The test statistic for this is mean-1000/(sd/sqrt(n))
Mean = 1024
sd=43
n=20

So the t-statistic here is (1024-1000)/(43/sqrt(20))
= 2.50 (to 2 dp)

2) Here you have been given the test statistic (as if calculated from above) = 0.57
We know that there were 10 subjects in the sample.
So we compare the value of 0.57 to the values of the t-distribution with 10 degrees of freedom.

If you look at the table of percentage points for the t distribuition you find that t=0.559 for p=0.5 and t=0.727 for p=0.4. So we know that the p-value for our test is somewhere between 0.4 and 0.5.
So the only statement that is true is b)