# Stat 160 postquiz over sections 9.1 - 9.4

This work is to be submitted for credit. Attempt all problems. Make sure you have attempted all problems before you submit. You may solve the problems several times, but only the first submission gets credit. Remember, don't hit the enter key until you are ready to submit this quiz.

### Please fill out the information below.

1.     Consider the two data sets (from independent populations) given below. What are the estimates of Delta (triangle symbol) (location of Y population - location of X population) using the Wilcoxon, Median, and Mean, respectively.(Hint: Since this is a two sample test, you could do this by hand or use your Class Codes)
```X:    8    13    111

Y:   18    12     14    12```

0, 0, -30
6, 0, -30
0, 0, -28.33
7, 5.5, -28.33
2.     Consider two samples, X and Y, randomly taken from two independent populations. Determine the Wilcoxon estimate of Delta (the triangle symbol), the difference in location between the two populations.(Hint: Again, your Class Codes can check your answer if you do this problem by hand)
```X:    12   16   18   25   30

Y:     8   10   19   22   28

```

0
10
-3
8.5
3.     Polls concerning the president's approval rating were taken in two states, A and B. Which of the following is an estimate of the difference in approval ratings between the two states?
```           Approve      Disapprove
State A      25            38
State B      44            40

```

19
-19
-.020
.127
4.     The following are 100 estimates of Delta obtained via 100 resamples. What is a 95% confidence interval for Delta based on resampling?
```-2.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0
-1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0
-1.0    -1.0    -1.0    -1.0    0.0     0.0     0.0     0.0     0.0     0.0
0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0
0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0     0.0
0.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0
1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0
1.0     1.0     1.0     1.0     1.0     1.0     1.0     1.0     2.0     2.0
2.0     2.0     2.0     2.0     2.0     2.0     2.0     2.0     2.0     2.0
2.0     2.0     2.0     2.0     2.0     2.0     2.0     2.0     3.0     3.0

```

(95,100)
(-1.0, 2.0)
(-2.0, 3.0)
(-1.0, 1.0)
5.     Consider the following situation:
Hypothesis test
• H0: Delta is zero
• HA: Delta is not zero
Say the 95% confidence interval for Delta happens to be (-10,10). What would be your conclusion? Reason?

Reject H0. Zero is in the interval.
Accept H0. The difference between the two confidence limits is zero.
Accept H0. Zero is in the interval.
Accept H0. Zero is half way between -10 and 10.