Brett is performing a hypothesis test in which the population mean is 310 and the standard deviation is 20 His sample data has a mean of 295 and a sample size of 50 Which of the following correctly depicts the z -statistic for Brett’s data?

Use the z-statistic formula: z = (sample mean − population mean) ÷ (population standard deviation ÷ √sample size). Substituting Brett’s values gives z = (295 − 310) ÷ (20 ÷ √50) ≈ −15 ÷ 2.83 ≈ −5.30. The correct choice is negative 5.30.

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