Question
In: Statistics and Probability
The marks on a statistics midterm test are normally distributed with a mean of 75 and...
The marks on a statistics midterm test are normally distributed with a mean of 75 and a standard deviation of 6. What is the probability that a sample of 50 exams has a sample mean between 74 and 75?
a. 0.3810
b. 0.1210
c. 0.4641
d. 0.3790
e. 0.1190
Solutions
Expert Solution
Solution :
Given that ,
mean = 
= 75
standard deviation = 
= 6
n = 50
= 75
= /
P(74< <
75) = P[(74-75) / 0.849< (
-
) / < (75-75) /0.849 )]
= P( -1.18< Z <0 )
= P(Z <0) - P(Z < -1.18)
Using z table
=0.5 -0.1190
PROBABILITY =0.3810
orchestra answered 3 years agoRelated Solutions
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