QUESTION 1

1. Consider two classes of business statistics. Suppose that average test score for the first class is 80 and the average test score for the second class is 78. What is the point estimate for the difference in the mean test scores? Answer to as many decimal places as necessary.

1.5 points

QUESTION 2

1. Consider two classes of business statistics. Suppose that average test score for the first class is 79 and the average test score for the second class is 84.2. What is the point estimate for the difference in the mean test scores? Answer to as many decimal places as necessary.

1.5 points

QUESTION 3

1. You are going to test a hypothesis concerning the difference between two population means. One of the steps to do this is to find the standard error. Suppose you have two samples with 50 observations each and standard deviations of 74.1 and 62.7. What is the standard error? Answer to two decimal places.

1.5 points

QUESTION 4

1. You are going to test a hypothesis concerning the difference between two population means. One of the steps to do this is to find the standard error. Suppose you have two samples with 40 observations each and standard deviations of 71.2 and 102.8. What is the standard error? Answer to two decimal places.

1.5 points

QUESTION 5

1. You are going to test a hypothesis concerning two means where the null hypothesis involves a difference of 0. Suppose that your two sample means are 29.3 and 35.4 while the estimated standard error is 3.6. What is the test statistic? Answer to two decimal places.

1.5 points

QUESTION 6

1. You are going to test a hypothesis concerning two means where the null hypothesis involves a difference of 0. Suppose that your two sample means are 50.5 and 42 while the estimated standard error is 5.3. What is the test statistic? Answer to two decimal places.

1.5 points

QUESTION 7

1. Suppose that the average weekly wage for women in the US is around $740 (see BLS report) while the average weekly wage for men is around $900. Suppose that the respective sample sizes are 1000 each and the standard deviations are $300 and $450. To test for the equality of the wages for the two populations what is the test statistic? Answer to two decimal places. Hint: your number should be negative.

1.5 points

QUESTION 8

1. Consider the previous problem where the average wage for women was $740 and for men it was $900 and you found a test statistic. Suppose you conduct your hypothesis test with a .05 level of significance. True or false: You reject the null hypothesis of equality.TrueFalse

1.5 points

QUESTION 9

1. In a paper by Lavy and Sand the authors investigate whether teachers are biased in how they grade students (among other things). You can find the paperhereor publicly available on the internethere(unless the author has moved it). Read up to "Identification and Estimation" on page 11. The tests that the students take for which some results are reported in their Table 2 were taken in which grade?

   3rd grade.

   5th and 6th.

   7th and 8th.

   9th.

   11th.

1.5 points

QUESTION 10

1. In a paper by Lavy and Sand (availablehere, again read to page 11) the authors suggest that teachers have a favorable bias for boys in

   English.

   Math.

   Hebrew.

   Chemistry.

   English, Hebrew, and math.

1.5 points

QUESTION 11

1. In a paper by Lavy and Sand (availablehere, again read to page 11) the authors report some summary statistics on test scores, see Table 2 in the paper. In the paper the test scores are converted to and reported as

   percentiles.

   t scores.

   z scores.

   gradient scores.

   matriculation scores.

1.5 points

QUESTION 12

1. Looking at Table 2 in the Lavy and Sand paper what is the point estimate for the difference in boys and girls "School Score Exams" for Hebrew? Answer to 3 decimal places. Report your number as a positive value.

2 points

QUESTION 13

1. Looking at Table 2 in the Lavy and Sand paper what is the point estimate for the difference in boys and girls "School Score Exams" for Hebrew you found a point estimate for the difference in the previous question. In order to test the hypothesis that the average scores are the same for boys and girls you will also need to calculate the standard error. Assume that the standard deviations are 1 for both boys and girls and that there are 4000 boys and 4000 girls; those number are slightly different from in the paper but close so use the numbers I just gave you. What is the standard error? Answer to 4 decimal places.

2 points

QUESTION 14

1. Now use the point estimate of the difference in boys and girls scores (using a positive value) and the standard error you just calculated to find a test statistics to test the hypothesis that boys and girls score the same on Hebrew exams. What is the test statistic? Answer to 1 decimal place and make sure your number is positive (if you found the point estimate of the difference as a negative value then just take the absolute value).

2 points

QUESTION 15

1. Given the correct test statistic you found in the previous problem you reject the null hypothesis that boys and girls have the same average score on Hebrew tests using a .05 level of significance.TrueFalse

1.5 points

QUESTION 16

1. Hypothesis testing and specifically hypothesis testing for the difference in two means can be useful when investigating whether two populations are being treated equally or performing equally and such questions do arise in business (comparing two production processes), public policy (comparing outcomes of social programs) and legal settings (such as in discrimination cases).TrueFalse

1.5 points

QUESTION 17

1. For a given standard error, the larger the difference between two point estimates the greater the p-value for a test of the equality of means. (Hint, try it with two sets of numbers and the same standard error and see which one has the larger p-value then look at it to see if that was a coincidence or if that will always be the case).TrueFalse

1.5 points

QUESTION 18

1. The test statistic for a hypothesis test concerning the equality of two means when the standard deviations are known and the samples are independent with more than 30 observations each follows which distribution?

   t

   z

   F

   Chi square

1 points

QUESTION 19

1. The test statistic for a hypothesis test concerning the equality of two means when the population standard deviations are not known and the samples are independent with more than 30 observations each follows which distribution?

   t

   z

   F

   Chi square

1 points

QUESTION 20

1. The test statistic for a hypothesis test concerning the equality of two means when the population standard deviations are not known and the samples are matched (or paired) follows which distribution?

   t

   z

   F

   Chi square

Hullo again, I need these before 8pm tonight if you can.