Stats A simple random sample of FICO scores is listed below. The mean FICO score is reported to be 678. Assuming that the standard deviation of all FICO scores is known to be 58.3, use a 0.01 significance level to test the claim that these sample FICO scores come from a population with a mean equal to 678. DATA: 714, 751, 664, 789, 818 , 779, 698, 836, 753, 834, 693, 802.

Step-by-step explanation:

The sample mean is:

(714+751+664+789+818+779+698+836+753+834+693+802) / 12

≈ 760.9

At 0.01 significance level and 11 degrees of freedom, the critical value is t = 3.106.

The standard error is 58.3 / √12 = 16.8.

The confidence interval is:

760.9 ± 3.106 × 16.8

(708.6, 813.2)

678 is outside of the confidence interval, so we can conclude with 99% confidence that the sample does not come from a population with a mean of 678.

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step-by-step explanation: