# Stat 160 Post-Quiz #4, Over Sections 3.1 - 4.3

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1. There are 30 students in a class of which 20 are girls. A group of 7 students is to be selected to work together. Based on the following 15 resamples (numbers 1-20 stand for girls), estimate the probability of selecting at least 5 girls in this group.

0.333
0.133
0.667
0.867

2. Referring to the situation in #1, what is the error of estimation?

0.015
0.122
0.243
0.063

3. Assume that in a certain country,C, 23% of deaths are caused by the disease D. In other words, the probability that a citizen of C will die of D is .23. Suppose we want to know the probability that 3 of the next 10 unrelated deaths are caused by D. We decide to perform 100 resampling trials to determine the probability. So we let 1-23 represent D and 24-100 represent not D. Which of the following is a correct input to the class resampling code?

Number of trials = 100
Minimum Value = 1
Maximum Value = 23
Number to sample = 10
With Replacement

Number of trials = 100
Minimum Value = 1
Maximum Value = 23
Number to sample = 10
Without Replacement

Number of trials = 100
Minimum Value = 1
Maximum Value = 100
Number to sample = 10
With Replacement

Number of trials = 100
Minimum Value = 1
Maximum Value = 100
Number to sample = 3
Without Replacement
4. Suppose X is the number spun on a spinner with the numbers 1, 2, 3 and 4 on it. Suppose the probaility of a 1 is 0.2, of a 2 is 0.2, and of a 3 is 0.2. What is the probability that X is 4?

0.30
0.20
0.00
0.40

5. Suppose X is the number spun on a spinner with the numbers 5, 6 ,7 and 10 on it. Suppose the probaility of a 5 is 0.2, of a 6 is 0.3, and of a 7 is 0.1, and of a 10 is 0.4. What is the mean of X?

7.5
6.5
0.4
10