Statistics 1. Select the most appropriate response. The *median* LSAT score repo
ID: 3023966 • Letter: S
Question
Statistics 1. Select the most appropriate response. The *median* LSAT score reported by a Law School is 170. Which of the following is not correct?
A)half of the students have an LSAT score of 170
B)half of the students have an LSAT score of 170 or below
C)the fiftieth percentile of students’ LSAT score is 170
D)half of the students have an LSAT score higher than 170
2. Which of the three histograms shown summarizes the data set with the smallest standard deviation?
A) 1
B) 2
C) 3
3.
Lengths of pregnancies of humans are normally distributed with a mean of 265 days and a standard deviation of 10 days. Use the Empirical Rule to determine the percentage of women whose pregnancies are between 255 and 275 days.
A) 95%
B) 99.7%
C) 68%
D) 50%
Explanation / Answer
3)mean = 265
standard dev = 10
For x = 255 , z = (255 - 265) / 10 = -1 and for x = 275, z = (275 - 265) / 10 = 1
Hence P(255 < x <275) = P(-1 < z < 1) = [area to the left of z = 1] - [area to the left of -1]
= 0.8414 - 0.1587 = 0.6827
= 68% hence option c is correct