3. A random sample of 17 wolf litters in Ontario, Canada, gave an average of x1 = 4.9 wolf pups per litter, with estimated sample standard deviation s = 1.0. Another random sample of 6 wolf litters in Finland gave an average of x2 litter, with sample standard deviation s2 = 1.2. = 2.8 wolf pups per a. Find an 85% confidence interval for4, - 42, the difference in population mean litter size between Ontario and Finland b. Examine the confidence interval and explain what it means in the context of the problem. Does the interval consist of numbers that are all positive, all negative, or different signs? At the 85% level of confidence, does it appear that the average litter size of wolf pups in Ontario is greater than the average litter size in Finland?

An electrical engineer wishes to compare the mean lifetimes of two types of transistors in an application involving high-temperature performance. A sample of 60 transistors of type A were tested and were found to have a mean lifetime of 1827 hours and a standard deviation of 174 hours. A sample of 180 transistors of type B were tested and were found to have a mean lifetime of 1658 hours and a standard deviation of 231 hours. Let ux represent the population mean for transistors of type A and µy represent the population mean for transistors of type B. Find a 95% confidence interval for the difference uy – µy . Round the answers to three decimal places. The 95% confidence interval is

a group of 59 randomly selected students have a mean score of 29.5 with a standard deviation of 5.2 on a placement test. what is the 90% confidence interval for the mean score, u, of all students taking the test?

The president of a large university wishes to compare the standard deviation of the ages of students presently enrolled to previous years. The distribution of ages has been approximately normal. Find the 90% confidence interval for the population standard deviation of the student ages of the University. A random sample of 20 university students has a standard deviation of 6.1 years in a mean of 23.8 years what is the confidence interval of the population standard deviation?

Suppose the mean height in inches of all 9th grade students at one high school is estimated. The population standard deviation is 3 inches. The heights of 7 randomly selected students are 72, 61, 74, 68, 64, 66 and 64. x¯ = Margin of error at 95% confidence level = 95% confidence interval = [ , ]

An agricultural researcher plants 14 plots with a new variety of corn. The average yield for these plots is X = 155 bushels per acre. Assume that the yield per acre for new variety of corn follows a normal distribution with unknown mean and a calculated sample standard deviation s = 10 bushels. A 90% confidence interval for the unknown mean is

A recent study of 28 randomly selected employees of a company showed that the mean ofdistance they traveled to work was 14.3 miles. The standard deviation of the sample was 2.0miles. Find the 95% confidence interval of the true mean.

A ecologist wishes to estimate the mean lifespan for a specific species of bird. Assume that bird lifespan is normally distributed and that each bird's lifespan is independent of all others. The researcher analyzes a random sample of n=7 deceased birds to find out how long they lived for. It is found that the mean lifespan in the sample is y= 5 4 years with standard deviation s=13 years. Choose the correct formula for a 95% confidence interval for the true mean lifespan. X± to.975,n O xt to.975,n-1 n-1 O none of these X+ Z0.975 O x+ to.975,n-1' O xt to.975,n-15

A random sample of 9 observations from a normally distributed population produced a mean x̅ =12.4 and a standard deviation s= 2.8. find a 99% confidence interval for the population mean?

A research article reported that for a random sample of 850 meal purchases made at fast food chain A, the mean number of calories was 1,004, and the standard deviation was 489. For a random sample of 2,108 meal purchases made at fast food chain B, the mean number of calories was 905, and the standard deviation was 622. Based on these samples, is there convincing evidence that the mean number of calories in fast food chain B meal purchases is less than the mean number of calories in fast food chain A meal purchases? (Test the relevant hypotheses using a 0.05 level of significance. Use ?1 for fast food chain B and ?2 for fast food chain A.)   State the appropriate null and alternative hypotheses.   Find the test statistic and P-value. (Use SALT. Round your test statistic to one decimal place and your P-value to three decimal places.) t= P-value=   State the conclusion in the problem context. We fail to reject H0. There is convincing evidence that the mean number of calories in fast food…