25. Use the normal distribution of SAT critical reading scores for which the mean is 503 and the standard deviation is 110. Assume the variable x is normally distributed. left parenthesis a right parenthesis What percent of the SAT verbal scores are less than 675? left parenthesis b right parenthesis If 1000 SAT verbal scores are randomly selected, about how many would you expect to be greater than 525? left parenthesis a right parenthesis Approximately nothing% of the SAT verbal scores are less than 675. (Round to two decimal places as needed.)
a) P(X < 675)
= P((X - )/
< (675 -
)/
)
= P(Z < (675 - 503)/110)
= P(Z < 1.56)
= 0.9406 = 94.06%
b) P(X > 525)
= P((X - )/
> (525 -
)/
)
= P(Z > (525 - 503)/110)
= P(Z > 0.2)
= 1 - P(Z < 0.2)
= 1 - 0.5793
= 0.4207
Expected number of SAT verbal scores = 1000 * 0.4207 = 420.7 = 421
Get Answers For Free
Most questions answered within 1 hours.