Question

Felip recorded 75 numerical observations on a certain variable and then calculated the mean x¯ and the standard deviation s for the observations. To help decide whether a normal model is appropriate, he created the following chart. The figure presents a line that is divided into 5 sections labeled from left to right a, b, c, d, and e. Section C is approximately double the size of the other sections. There are 4 tick marks on the line segment, as follows. The tick mark separating sections a and b is labeled x bar minus 2 s. The tick mark separating sections b and c is labeled x bar minus s. The tick mark separating sections c and d is labeled x bar plus s. The tick mark separating sections d and e is labeled x bar plus 2 s. In Felip’s chart, the letters a,b,c,d,e represent the number of observations falling in each interval. Which of the following lists of counts for a,b,c,d,e, respectively, is the best indicator that the variable can be modeled with a normal approximation?

Answer 1

Answer:

The answer is B

Explanation:

Normal distributions are unimodal with a bell curve, and the numbers listed in B best fit that description.