23. If all else remains unchanged, a decrease in the level of confidence will le

Question

23. If all else remains unchanged, a decrease in the level of confidence will lead to a interval A. Narrower B. Wider C. Less significant D. Biased 24. For a random sample of 9 women, the average resting pulserate is x 76 beats per minute, an the sample standard deviation is s 5. The standard error of the sample mean is? A. 0.557 B. 0.745 C. 1.667 D. 2.778 25. If a distribution has a mean of 100 and a standard deviation of 15, what value would be +2 standard deviations from the mean? A. 70 B. 115 C. 130 D. 85 26. When events are independent of one another: A. The probability all occur is the addition of the probabilities each will occur B. They are mutually exclusive C. Knowing the outcome for one event, provides no information about whether the others wi occur or not D. The probability that one occurs depends on whether or not the others have occurred 27. For a two-tail test, the null hypothesis will be rejected at the 0.05 level of significance if the value of the standardized test statistic z is: A. smaller than 1.96 or greater than -1.96 B. greater than -1.96 or smaller than 1.96 C. smaller than -1.96 or greater than 1.96 D. greater than 1.645 or less than -1.645

Explanation / Answer

Hi,

I am going to answer the first four questions.

23. First of all when you say a confidence interval you set a range of values with some level of confidence. Now suppose you to be absolutely certain about the range of values a statistic can take. For that your interval would range from negative infinity to positive infinity. Now as you decrease the level of confidence your confidence interval will be narrower.

24. The mean of the sampling distrbituon is as follows
     x = and x = / sqrt(n). where LHS represents parameters of sample mean's distribution. The required answer will be 5/sqrt(9) = 5/3 =1.667

25. Since you need the value +2 standard deviation from mean = 100+2*15=130.

26. When we say events are independent of each other it implies that happening on one doesn't affect / influence happening of another. This is in line with option C.

27. A two tail test will be rejected if absolute value of the test statistic is greater than absolute value of critical value. The critical value is 1.96 for a significance level of 0.05. This corresponds to value smaller than -1.96 and greater than1.96. Option C

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.