Question

ATM Withdrawals According to Crown ATM Network, the mean ATM withdrawal is $67.
Assume that the standard deviation for withdrawals is $35. Determine the probability of obtaining a
sample mean withdrawal amount between $70 and $75.
First determine the standard deviation of the sampling distribution






Calculating X-values
Press and select Option #3 invNorm(
X-value = invNorm(area to the LEFT, mean, std.dev)
The combined (verbal + quantitative reasoning) score on the GRE is normally distributed with mean
1049 and standard deviation 189. What is the score of a student whose percentile rank is at the 85th

Answer 1

a) In Excel or any other program, you can use the following normal cumulative function to determine the probability:

The standard deviation of sampling distribution will be: 35/√n, here n is the sample size

The formula is:
=NORM.DIST(75,67,s,TRUE)-NORM.DIST(70,67,s,TRUE)
TRUE because we are using a cumulative distribution
s is the standard deviation calculated. The sample size is not given in the question.

You will get the output using the above formula

b) Use invnorm function as follows:
invNorm(0.85, 1049, 189)
Output: 1244.886 (Score)