A researcher studying the lifespan of a certain species of bacteria. A preliminary sample of 25 bacteria reveals a sample mean of = 70 hours with a standard deviation of s = 7 hours. He would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.5 hours at a 99% level of confidence. What sample size should you gather to achieve a 0.5 hour margin of error? He would need to sample bacteria.

When engaging in weight-control (fitness/fat burning) types of exercise, a person is expected to attain approximately 60% of his or her maximum heart rate. For 20-year-olds, this rate is approximately 120 bpm. A simple random sample of one hundred 20-year-olds was taken, and the sample mean was found to be 107 bpm, with a standard deviation of 45 bpm. Researchers wonder if this is evidence to conclude that the expected level is actually lower than 120 bpm. To determine this, we test the following hypotheses: Ho: H= 120 versus H₂ μ< 120 Suppose the mean and standard deviation obtained were based on a sample of size 25 rather than 100.

Ann thinks that there is a difference in quality of life between rural and urban living. She collects information from obituaries in newspapers from urban and rural towns in Idaho to see if there is a difference in life expectancy. A sample of 3 people from rural towns give a life expectancy of xr¯=79��¯=79 years with a standard deviation of sr=7.57��=7.57 years. A sample of 14 people from larger towns give xu¯=82��¯=82 years and su=5.48��=5.48 years. Does this provide evidence that people living in rural Idaho communities have different life expectancy than those in more urban communities? Use a 5% level of significance. (a) State the null and alternative hypotheses: (Type ‘‘mu_r′′‘‘��_�″ for the symbol μr�� , e.g. mu_rnot=mu_u��_����=��_� for the means are not equal, mu_r>mu_u��_�>��_� for the rural mean is larger, mu_r<mu_u��_�<��_� , for the rural mean is smaller. )H0�0 =  equation editor Equation Editor Ha�� =  equation editor Equation Editor   (b) The degree of…

A medical statistician wants to estimate the average weight loss of people who are on a new diet plan. In a preliminary study, he guesses that the standard deviation of the population of weight loss is about 12 pounds. How large a sample should he take to estimate the mean weight loss to within 3 pounds, with 93% confidence? Sample Size = xxxxxxxxx

A man measures his heart rate before using a treadmill and then after walking ona treadmill for 10 minutes on 7 separate days. His mean heart rate at baseline and10 minutes after treadmill walking is 85 and 93 beats per minute (bpm), respectively. The mean change from baseline to 10 minutes is 8 bpm with a standarddeviation of 6 bpm.(a)  What test can we use to compare pre- and post-treadmill heart rate?(b)  Implement the test in 2a, and report a two-tailedp-value.(c)  Provide a 90% confidence interval (CI) for the mean change in heart rate afterusing the treadmill for 10 minutes.(d)  What is your overall conclusion concerning the data?   this is a review question of ch8 bernard rosner. the solution is not provided at bartleby for this review question

You are a researcher studying the lifespan of a certain species of bacteria.  A preliminary sample of 35 bacteria reveals a sample mean of ¯x=76x¯=76 hours. The population standard deviation is known to be 5.6  hours.  You would like to estimate the mean lifespan for this species of bacteria to within a margin of error of 0.4 hours at a 90% level of confidence. How many more bacteria should you sample to achieve a 0.4 hour margin of error? n =     bacteria

If a distribution has a mean of 46 and a standard deviation of 1, what value would be -2 standard deviations from the mean?

The sample mean of depression scores of 16 fifth graders was 4.4 with standard deviation of 8. If the population mean of this depression score is 6, what is the calculated t score for this sample?

A random sample of 100 observations from a quantitative population produced a sample mean of 28.0 and a sample standard deviation of 6.5. Use the p-value approach to determine whether the population mean is different from 31.

A researcher is interested in learning about average online hours per day for Camosun College students. Data is gathered from 50 students - mean online hours is 7.52 with a standard deviation of 2.85. Calculate the 95% CI (or alpha at 0.05) and interpret your results in a full sentence. Now calculate a 99% CI for the above. How does your answer change?   If the researcher sampled a group of 24 students and the new calculated mean and standard deviation are the same as with the larger group of 50, would the 99% CI change from b above? If yes, in what way?