jodi and laura went out to dinner at their favorite sandwich shop . if their bill w's $21.95 and they wanted to leave a 15% tip
1 answer:
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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
Answer:
The proportion of individuals score at most 74 points on this test is 70%.
Step-by-step explanation:
The complete question is:
Suppose that the scores on a reading ability test are normally distributed with a mean of 70 and a standard deviation of 8. What proportion of individuals score at most 74 points on this test? Round your answer to at least four decimal places.
Solution:
Let <em>X</em> represent the scores on a reading ability test.
It is provided that .
Compute the probability that an individuals score is at most 74 points on this test as follows:
Thus, the proportion of individuals score at most 74 points on this test is 70%.