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(4 points) For each problem, select the best response. (a) Heights of mature tri

ID: 3274982 • Letter: #

Question

(4 points) For each problem, select the best response.

(a) Heights of mature triffids are Normally distributed with mean 1.86 meters and standard deviation 0.23 meters. About what percentage of mature triffids are taller than 2 meters?

A. About 98% B. About 2% C. About 73% D. About 27% E. About 23%

(b) For a standard Normal distribution, find the approximate proportion of observations less than 1.36.

A. 0.9131 B. 0.8631 C. 0.1869 D. 0.9631 E. 0.0869

(c) For a standard Normal distribution, find the approximate proportion of observations between -0.25 and 0.5.

A. 0.2402 B. 0.2902 C. 0.7098 D. 0.3402 E. 0.8098

(d) For a Normal distribution with mean 190 and standard deviation 15, 35 percent of the observations are less than what value?

A. 202.64 B. 147.38 C. 165.8 D. 184.22 E. 221.06

Explanation / Answer

a) P(X > 2)

= P(z > (2 - 1.86)/0.23)

= P(z > 0.61)

= About 27%

Option D is correct.

b) Option A is correct.

c) Option B is correct.

d) Option D is correct.