Which statement is wrong? A. Normal distribution is uniquely determined by the mean and standard deviation
B. All normal distributions can be transformed to the standard normal distribution
The mean and the median are the same for normal distributions
D. The larger the standard deviation in normal distribution, the less spread out the data
from the center.
The hours of sleep per week night among college students, is found to be normally distributed
with a mean of 7 hours and a standard deviation of 1 hour.
What range contains the middle 95% of hours slept per week night among college students?
A. 6 to 8 hours
B. 5 and 9 hours
C 1 to 10 hours
College students sleep distribution is N(7,1). The percentage of college students that need at
least 8 hours per night is about?
A. -0.50
B. 0.25
C. 0.50
College students sleep distribution is N(7,1). The percentage of college students that need at
least 8.5 hours per night is about?
A. 2.5%
B. 6.68%
C. 93.32%
What's the Z-socre corresponding to the upper tail area 0.50?
A. Z-1.645
B. Z-1.96
CZ-1.645
D. Z=-1.96
Scores on the SAT verbal test in recent years follow approximately the N(515,110 distribution
The proportion of students scoring between 460 and 550 is the closest to?
A. 0.309
B. 0.317
C. 0.626
D. 0.818