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The GMAT test is required for admission to most graduate programs in business. In a recent year, the GMAT test scores were normally distributed with a mean of 550 and standard deviation of 100.

A. Find the first quartile for the distribution of GMAT scores.
B. Find the median for the distribution of GMAT scores.
C. Find the ninety-fifth percentile for the distribution of GMAT scores.

• stats. -

A few hints:

A. First quartile is the 25th percentile.
B. Second quartile (median) is the 50th percentile.
C. 95th percentile is most of the distribution.

Find the z-scores using a z-table for each of these percentiles.

Use z-score formula to find the scores at each percentile.

Formula:
z = (x - mean)/sd
mean = 550
sd = 100

Solve for x in each case.

Note: In a normal distribution, the mean, median, and mode are the same.

• stats. -

so would part a be

.4207=(x-550)/100 ?

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