A department store, on average, has daily sales of $28,372.72. The standard deviation of sales is $2000. On Tuesday, the store sold $34,885.21 worth of goods. Find Tuesday's zscore and was Tuesday's zscore a significantly high value?

Question

Business

Emily Lee

4 May, 18:38

A department store, on average, has daily sales of $28,372.72. The standard deviation of sales is $2000. On Tuesday, the store sold $34,885.21 worth of goods. Find Tuesday's zscore and was Tuesday's zscore a significantly high value?

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Answers (1)

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Bethany Garrison · Answer 1

Z-score = 3.26

Explanation:

The Z-score formula to employ is given as follows:

Z = (X - U) : SD ... (1)

Where,

Z = the z-score = ?

X = Tuesday's sales = $34,885.21

U = Average or mean of daily sales = $28,372.72

SD = Standard deviation of sales = $2,000

Substituting each variable into equation (1), we can calculate the z-score as follows:

Z = ($34,885.21 - $28,372.72) : $2,000

= $6,512.49 - $2,000

= 3.26

The Z-score of 3.26 implies that the Tuesday's sales is 3.26 standard deviation above the mean. Given the empirical rules of 95%, the Tuesday's sales is not significantly higher than 3 standard deviations above the mean.

Therefore, the sales on Tuesday were good.