Basic Statistics > A-Level Question Paper > Sophia Introduction to Statistics Unit 5 Milestone 5 (All)

Sophia Introduction to Statistics Unit 5 Milestone 5

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Joe is measuring the widths of doors he bought to install in an apartment complex. He measured 72 doors and found a mean width of 36.1 inches with a standard deviation of 0.3 inches. To test if the d... oors differ significantly from the standard industry width of 36 inches, he computes a z-statistic. What is the value of Joe's z-test statistic? 2.83 -1.81 -2.83 1.81 RATIONALE 6/29/2020 Sophia :: Welcome https://www.sophia.org/spcc/introduction-to-statistics-2/milestone_take_feedbacks/4324532 2/22 If we first note the denominator of Then, getting the z-score we can note it is This tells us that 36.1 is 2.83 standard deviations above the value of 36. Note that when you round some values you may get slightly different results, but the results should be relatively close to this final calculated value. CONCEPT Z-Test for Population Means 2 Emile has calculated a one-tailed z-statistic of -1.97 and wants to see if it is significant at the 5% significance level. What is the critical value for the 5% significance level? Answer choices are rounded to the hundredths place. -2.33 0 -1.04 -1.64 RATIONALE Recall that when a test statistic is smaller than in a left-tailed test we would reject Ho. The closest value to 5%, or 0.05, in the table would be between 0.0505 and 0.495. 0.0505 corresponds with a z-score of -1.64 0.0495 corresponds with a z-score of -1.65. We need to calculate the average of the two z-scores to get a z-score of -1.645. CONCEPT How to Find a Critical Z Value [Show More]

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