engineer who is studying the tensile strength of a steel alloy intended for use in golf afts knows that tensile strength is approximately normally distributed with s=25 random sample of 25 specimens has a mean tensile strength of x = 3490 psi. Test the hypothesis that the mean strength is NOT 3500 psi by using the p-value. Use α=0.05. Test the hypothesis in part (a) using a two-sided confidence interval on mean tensile strength.

Researchers measured the length of time people spend brushing their teeth. For the 154 subjects in their study, the mean was 72.8 seconds with a standard deviation of 23. 5 seconds. Use this information with a 0.10 significance level to test the claim that the mean teeth brushing time was less than 80 seconds. What is/are the critical value(s)? TTTArial 3 (12pt) v T- = - E - V · P 只igv

11% of all Americans suffer from sleep apnea. A researcher suspects that a different percentage of those who live in the inner city have sleep apnea. Of the 344 people from the inner city surveyed, 34 of them suffered from sleep apnea. What can be concluded at the level of significance of αα = 0.01? The test statistic=      (please show your answer to 3 decimal places.)   The p-value =       (Please show your answer to 4 decimal places.)

An experiment is conducted to compare the maximum load capacity in tons (the maximum weight that can be tolerated without breaking) for two alloys A and B It is Kknown that the two standard deviations in load capacity are equal at 7 tons each. The experiment is conducted on 50 specimens of each alloy (A and B) and the results are X = 75.8. X = 71.8, and X-X=4. The manufacturers of alloy A are convinced that this evidence shows conclusively that Hug and strongly supports the claim that their alloy is superior. Manufacturers of alloy 8 claim that the experiment could easily have given X-X 4 even if the two population means are equal. Complete parts (a) and (b) below. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. (a) Make an argument that manufacturers of alloy B are wrong. Do it by computing P(XA-XB41 PA-HB) P(XA-X > 4) - @

A researcher claims that the average wind speed in a certain city is 8 miles per hour. A sample of 32 days has an average wind speed of 8.2 miles per hour. The standard deviation of the population is 0.6 mile per hour. At  0.05, is there enough evidence to reject the claim? STEP 2. The critical value (s) is/are: z1 =                        z2 =

To determine if their 1.33 centimeter galvanized pipes are properly adjusted, Fogarty Manufacturing has decided to use an X-Chart which uses the range to estimate the variability in the sample. Answer How to enter your answer Step 3 of 7: What is the Lower Control Limit? Round your answer to three decimal places. 1 ~ 3 Sample Mean Sample Range 1.33 1.3320 1.29 1.38 1.3300 Period obs1 obs2 obs3 obs4 obs5 1.34 1.29 1.35 2 1.35 1.35 3 1.34 1.35 1.36 1.29 1.29 1.31 1.32 1.33 1.34 1.3360 1.35 1.30 1.3340 1.32 1.38 1.3260 1.37 1.33 1.31 1.31 1.29 1.30 1.35 1.31 1,32 1.34 1.38 8 1.35 1.33 1.31 1.34 1.3180 1.33 1.3300 1.34 1.37 1.28 1.36 9 10 1.32 1.37 1.30 1.37 1.29 1.32 1.30 1.28 1.29 11 1.35 1.36 1.38 12 1.36 1.32 1.31 1.30 1.35 13 1.29 1.35 1.32 1.32 1.37 1.35 1.35 1.34 1.32 1.34 14 15 1.32 1.36 1.29 1.32 1.35 45 Table 67 Control Chart 1.35 1.28 Copy Table Average Values The average of the selected cell(s) is 1.340. Copy Value 1.3300 1.3440 1.3080 1.3400 1.3280 1.3300 1.3400 1.3280 0.06…

Suppose the mean IQ score of people in a certain country is 100. Suppose the director of a college obtains a simple random sample of 39 students from that country and finds the mean IQ is 104.5 with a standard deviation of 13.6. Complete parts (a) through (d) below. (a) Consider the hypotheses Ho: µ= 100 versus H,: µ> 100. Explain what the director is testing. Perform the test at the a = 0.10 level of significance. Write a conclusion for the test. Explain what the director is testing. Choose the correct answer below. O A. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually not equal to 100. OB. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually greater than 100. O C. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually not greater than 100. O D. The director is testing if the sample provided sufficient…

Suppose the mean IQ score of people in a certain country is 103. Suppose the director of a college obtains a simple random sample of 37 students from that country and finds the mean IQ is 107.4 with a standard deviation of 13.8. Complete parts (a) through (d) below. (a) Consider the hypotheses Ho: H= 103 versus H: u> 103. Explain what the director is testing. Perform the test at the a = 0.01 level of significance. Write a conclusion for the test. Explain what the director is testing. Choose the correct answer below. A. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually greater than 103. B. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually not equal to 103. O C. The director is testing if the sample provided sufficient evidence that the population mean IQ score is actually equal to 103. O D. The director is testing if the sample provided sufficient evidence that…