8.2 Suppose average pizza delivery times are normally distributed with an unknown population mean and a population standard deviation of six minutes. A random sample of 28 pizza delivery restaurants is taken and has a sample mean delivery time of 36 minutes. Find a 90% confidence interval estimate for the population mean delivery time. Solution A Identify values to plug into the formula i +( Za Write solution first as ī ± EBM: Write solution in interval notation: Solution B Chock v our "by, band" work by rupping 7lntonal tort:

What is the optimal time for a scuba diver to be on the bottom of the ocean? That depends on the depth of the dive. The U.S. Navy has done a lot of research on this topic. The Navy defines the "optimal time" to be the time at each depth for the best balance between length of work period and decompression time after surfacing. Let x = depth of dive in meters, and let y = optimal time in hours. A random sample of divers gave the following data. 16.1 22.7 25.3 1.98 32.2 38.3 51.3 20.5 y 2.78 1.88 1.03 0.75 2.38 2.20 (a) Find Ex, Ey, Ex, Ey", Exy, and r. (Round r to three decimal places.) Ex= Ey= Ey? - Exy = (b) Use a 1% level of significance to test the claim that p < 0. (Round your answers to two decimal places.) critical t= Conclusion O Fail to reject the null hypothesis. There is sufficient evidence that p < 0. O Fail to reject the null hypothesis. There is insufficient evidence that p < 0. Reject the null hypothesis. There is sufficient evidence that p < 0. Reject the null hypothesis.…

Heights​ (cm) and weights​ (kg) are measured for 100 randomly selected adult​ males, and range from heights of 135 to 188 cm and weights of 39 to 150 kg. Let the variable x be the height. The 100 paired measurements yield x=167.08 ​cm, y=81.32 ​kg, r=0.254​, and y=−109+1.07x. Find the best predicted value of y ​(weight) given an adult male who is 163 cm tall. Use a 0.05 significance level.     The best predicted value of y for an adult male who is 163 cm tall is   kg. ​(Round to two decimal places as​ needed.)

Stoaches are fictional creatures, sometimes mistaken for mome raths. Suppose a two-tailed t-test is conducted to test for a difference between the population means of adult female stoach weights and adult male stoach weights. The female sample has 13 weights, and the male sample has 7 weights. The t-statistic for the test is -0.20542. What is the p-value? (Give your answer to 4 decimal places.) p-value:

For 50 randomly selected speed dates, attractiveness ratings by males of their female date partners (x) are recorded along with the attractiveness ratings by females of their male date partners (y); the ratings range from 1 to 10. The 50 paired ratings yield x = 6.4, y = 6.0, r=-0.233, P-value = 0.104, and ŷ= 7.88 -0.292x. Find the best predicted value of y (attractiveness rating by female of male) for a date in which the attractiveness rating by the male of the female is x = 4. Use a 0.01 significance level. The best predicted value of y when x = 4 is (Round to one decimal place as needed.)

What is the optimal time for a scuba diver to be on the bottom of the ocean? That depends on the depth of the dive. The U.S. Navy has done a lot of research on this topic. The Navy defines the "optimal time" to be the time at each depth for the best balance between length of work period and decompression time after surfacing. Let x = depth of dive in meters, and let y = optimal time in hours. A random sample of divers gave the following data. 16.1 23.3 29.2 38.3 51.3 20.5 22.7 2.68 2.18 1.88 1.03 0.75 2.38 2.20 (c) Find S, a, and b. (Round your answers to five decimal places.) e' Se a = b = (d) Find the predicted optimal time in hours for a dive depth of x = 38 meters. (Round your answer to two decimal places.) hr (e) Find an 80% confidence interval for y when x = 38 meters. (Round your answers to two decimal places.) lower limit hr upper limit hr (f) Use a 1% level of significance to test the claim that ß < 0. (Round your answers to two decimal places.) t = critical t = (g) Find a 90%…

Match each Test Situation with the correct Critical Value. For a two-sided test, find only the positive value. Test Situation Two samples, 1 = 25.3, I2 H.: P1 - 2 po, and a 0.01 %3D Two samples, n = 28, Ha: µd > 0, and a 0.01 dv One sample, ni = - 35, п2 41, Ha: p1 – p2 0, and a = 0.01 %3D %3D One sample of x's and y's, n = 114, Ha: p < 0, and a = 0.001 One sample, o is known, n = 68, Ha:µ # Ho, and a = 0.05 One sample, o is unknown, n = 76, H. : µ < Ho, and a 0.05 Critical Value a. 1.960 b. -3.165 C. 2.473 d. 2.326 e. 2.576 f. -1.294 g. -1.665 h. 2.426

Heights​ (cm) and weights​ (kg) are measured for 100 randomly selected adult​ males, and range from heights of 133133 to 190190 cm and weights of 3737 to 150150 kg. Let the predictor variable x be the first variable given. The 100 paired measurements yield x overbarxequals=168.08168.08 ​cm, y overbaryequals=81.5781.57 ​kg, requals=0.3130.313​, ​P-valueequals=0.0020.002​, and ModifyingAbove y with caretyequals=negative 108−108plus+1.121.12x. Find the best predicted value of ModifyingAbove y with carety ​(weight) given an adult male who is 169169 cm tall. Use a 0.050.05 significance level.   The best predicted value of ModifyingAbove y with carety for an adult male who is 169169 cm tall is (answer)  kg. ​(Round to two decimal places as​ needed.)

What is the optimal time for a scuba diver to be on the bottom of the ocean? That depends on the depth of the dive. The U.S. Navy has done a lot of research on this topic. The Navy defines the "optimal time" to be the time at each depth for the best balance between length of work period and decompression time after surfacing. Let x = depth of dive in meters, and let y = optimal time in hours. A random sample of divers gave the following data. x 16.1 26.3 29.2 38.3 51.3 20.5 22.7 y 2.68 1.98 1.48 1.03 0.75 2.38 2.20   (b) Use a 1% level of significance to test the claim that ? < 0. (Round your answers to two decimal places.) t =   critical t =

The pulse rates of 176 randomly selected adult males vary from a low of 40 bpm to a high of 116 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 2 bpm of the population mean.   Assume that o= 10.1 bpm, based on the value  s = 10.1 bpm from the sample of 176 male pulse rates