In a normal distribution with a mean of 7.5 and a standard deviation of 3.5, fin

Question

In a normal distribution with a mean of 7.5 and a standard deviation of 3.5, find the probability of getting a score less than 12. ________ In a non-normal distribution with a mean of 125 and a standard deviation of 4.9. if 38 people are randomly selected, find the probability of less than 127. 0.994 0.817 0.658 Can't be determined Repeat # 16 with a random sample of 25 people. 0.658 0.802 0.979 Can't be determined Twenty seven students were randomly selected from a known normal population and the sample mean was 88. Assume the population standard deviation was 7.1. Construct a 99% confidence interval for the population mean. 84.19 to 91.81 84.49 to 91.51 81.99 to 94.01 85 59 to 90 41 You wish to estimate the mean with 95% confidence that the sample mean will be within 0.008. Find the sample size requires if the population standard deviation is estimated to be 0.01. 9 8 7 6

Explanation / Answer

Attempting 1 question per post, therefore solving the first question:

15.

Params of normal dist are given:

Mean = 7.5
Stdev = 3.5

We try to standarize the variable:

P(X<12) =P(Z< 12-7.5 / 3.5)

= P(Z<1.285)

= .9007

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