# Statistics

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T F 1. Hypothesis testing is a procedure based on sample evidence and probability theory to decide whether the hypothesis is a reasonable statement.

T F 2. For a one-tailed test using the 0.05 level of significance, the critical value for the z test is 1.645, but for t it is 1.96.

T F 3. An alternate hypothesis is a statement about a population parameter that is accepted when the null hypothesis is rejected.

T F 4. Records on a fleet of trucks reveal that the average life of a set of spark plugs is normally distributed with a mean of 22,100 miles. A manufacturer of spark plugs claims that its plugs have an average life in excess of 22,100 miles. The fleet owner purchased 18 sets and found that the sample average life was 23,400 miles, the sample standard deviation was 1,500 miles and the computed t = 3.677. Based on these findings, there is enough evidence to accept the manufacturer's claim at the 0.05 level.

T F 5. The region or area of rejection defines the location of all those values that are so large or so small that the probability of their occurrence under a true null hypothesis is rather remote.

T F 6. If the null hypothesis is ƒÝ„d 200 and the alternate hypothesis states that ƒÝ is less than 200, then, a two-tail test is being conducted. (ANSWER (False)

T F 7. If we do not reject the null hypothesis based on sample evidence, we have proven beyond doubt that the null hypothesis is true. ANSWER(True)

T F 8. The null hypothesis is rejected when a p-value is greater than a stated significance level.

9. Which of the following does NOT hold true for the t distribution?
A) Confidence intervals will be wider than for large samples.
B) The region of acceptance will be larger than for large samples.
C) A larger computed t value will be needed to reject the null hypothesis than for large samples using z.
D) There is only one t distribution.

10. Test at the 0.01 level the statement that 55% of those families who plan to purchase a vacation residence in Florida want a condominium. The null hypothesis is ƒà = 0.55 and the alternate is ƒà„j 0.55. A random sample of 400 families who planned to buy a vacation residence revealed that 228 families want a condominium. What decision should be made regarding the null hypothesis?
A) Do not reject it
B) Reject it
C) Cannot accept nor reject it based on the information given
D) None of the above

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What is the level of significance?