Answer:
P(57 < X < 69) = 0.1513
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
Find P(57 < X < 69):
This is the pvalue of Z when X = 69 subtracted by the pvalue of Z when X = 57. So
X = 69
has a pvalue of 0.9564
X = 57
has a pvalue of 0.8051
0.9564 - 0.8051 = 0.1513
P(57 < X < 69) = 0.1513
All points lie on a horizontal line
The square root of 5/2 is 2.236067978. The square root of 18 is 4.242640687. The total of 2.236067978 plus 4.242640687= 6.478708667.
If you rounded up to two decimal points. You will get 6.48. It depends what digit your question is telling you to round up to.
Hope it helps.