18. Obtain the t* critical value for a 90% confidence interval for the population mean when the sample size collected is n = 11. O a. 1.796 O b. 1.645 O c. 2.228 O d. 1.812 20. If we were to take many random samples of the same size from the same population, and for each sample calculate a confidence interval, then the is the proportion of confidence intervals that capture the population parameter. Fill in the blank. O a. sample proportion O b. p-value O c. significance level O d. confidence level 21. The width of a confidence interval calculated to estimate the population mean increases (gets wider) when: O a. The sample size increases (i.e. n increases from 50 to 100). O b. The confidence level percentage increases (i.e. confidence level increases from 90% to 95%). O c. The sample mean decreases (i.eX decreases from 30 to 20). O d. The sample standard deviation decreases (i.e. s decreses from 10 to 5)

22. In general, the correct interpretation of a 95% confidence interval for the population mean is: O a. We are 95% confident that the constructed confidence interval captures the unknown population mean. O b. If we sampled repeatedly, 95% of all sample means will fall within the confidence interval constructed from the first sample selected. O c. There is a 95% chance that 95% of all sample means from the population are captured by the confidence interval. O d. We are 95% confident that the sample mean used to build the confidence interval falls in the confidence interval 26. If you conduct a hypothesis test and, based on your p-value, you decide to reject the null hypothesis, which type of error can you commit? O a. Both Type I and Type Il error (both the first and second types of mistakes). b. Type I error (the first type of mistake) O c. Type II error (the second type of mistake) O d. Neither Type I nor Type Il error (neither the first nor the second types of mistakes).