1 If you are doing a statistical test with alpha05 and beta2

1. If you are doing a statistical test with alpha=.05 and beta=.20, what is your power?

2. The manufacturer of a certain toy claims that the mean lead content in this toy is 100 ppm. A sample of 100 such toys produced mean= 110 ppm. This would provide evidence against the manufacturer’s claim if we can show that _____________.

a.105.1 could reasonably occur by chance if the claim were true

b. 105.1 could rarely occur by chance if the claim were true

c. 100 could rarely occur by chance if the claim were true

d. 100 could reasonably occur by chance if the claim were true

3. Which of the following is affected when all the scores in a distribution are converted to z-scores? i)mean ii) standard deviation iii) variance iv) the shape of the distribution.

a. i and iv
b. iv only
c. ii and iii
d. i, ii, and iii
e. The correct answer is not listed here.

4. One thousand employees are given a standard test to measure job performance. The top 10 are to be given trips to Hawaii and the bottom 30 scorers are to be given trips back to training school. Assuming that the distribution is normal, M = 65 and SD = 10, what score must one get to be given a trip to Hawaii?

5. One thousand employees are given a standard test to measure job performance. The top 10 are to be given trips to Hawaii and the bottom 30 scorers are to be given trips back to training school. Assuming that the distribution is normal, M = 65 and SD = 10, what score must one get to end up back in training school?

Solution

1.

Note that power = 1 - beta.

Thus,

power = 0.80. [ANSWER]

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2. [OPTION B] 105.1 would rarely occur by chance if the claim were true.

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3. [OPTION D] i, ii, and iii

[The shape would not change]