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A department store manager has monitored the number of complaints received per week about poor service. The probabilities for numbers of complaints in a week, established by this review, are shown in the table. Answer Number of complaints 012 3 4 5 Probability 0.13 0.21 0.44 0.070. 0.06 0.09Save your answer What is the variance of complaints received per week? Please round your answer to the nearest hundredth Note that the correct answer will be evaluated based on the full-precision result you would obtain using Excel.

200 word answer

Answer 1

To calculate the variance of complaints received per week, we first need to find the mean or expected value of the number of complaints. This can be calculated by multiplying the number of complaints in each category by its corresponding probability, and then adding up the results.

Expected value = (0 x 0.13) + (1 x 0.21) + (2 x 0.44) + (3 x 0.07) + (4 x 0.06) + (5 x 0.09) = 2.54

Next, we can use the following formula to calculate the variance:

Variance = Σ[(x - µ)²P(x)]

where Σ = sum, x = number of complaints, µ = expected value, and P(x) = probability.

Using this formula and the probabilities given in the table, we get:

Variance = (0 - 2.54)²(0.13) + (1 - 2.54)²(0.21) + (2 - 2.54)²(0.44) + (3 - 2.54)²(0.07) + (4 - 2.54)²(0.06) + (5 - 2.54)²(0.09) = 1.4856

Rounding this answer to the nearest hundredth, we get a variance of 1.49.

In conclusion, the variance of complaints received per week is 1.49, meaning that the number of complaints is quite spread out around the mean, which is 2.54. This could indicate that the department store has some variability in its service quality, as the number of complaints can vary widely from week to week.