Provide an appropriate response. 1) Fifty percent of the people that get mail-or

Question

Provide an appropriate response. 1) Fifty percent of the people that get mail-order catalogs order something. Find the probability that six or seven of 9 people getting these catal ogs will order something. 2) Find the z- score that corresponds to the given area under the standard normal curve. 0.9564 3For the standard normal curve, find the z-score that corresponds to the 30th percentile. A) -0.12 B)-0.47 C)-0.53 D) -0.98 4) IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find thex- score that corresponds to az-score of 2.33. A) 139.55 B) 142.35 C) 125.95 D) 134.95

Explanation / Answer

1) p = 0.5

n = 9

P(X = x) = 9Cx * 0.5x * (1 - 0.5)9-x

P(X = 6 or 7) = P(X = 6) + P(X = 7)

                      = 9C6 * 0.56 * 0.53 + 9C7 * 0.57 * 0.52

                      = 0.1641 + 0.0703

                      = 0.2344

2) P(Z > z) = 0.9564

or, 1 - P(Z < z) = 0.9564

or, P(Z < z) = 0.0436

or, z = -1.71

3) Z-score for 30th percentile = -0.53

Option-C) -0.53

4) mean = 100

sd = 15

Z = (X - mean) /sd

or, 2.33 = (X - 100) / 15

or, X = 100 + 2.33 * 15

or, X = 134.95

Option-D) 134.95

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