Find the 90% confidence interval for the standard deviation of the lengths of pipes if a sample of 22 pipes has a standard deviation of 10.6 inches.

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…

Assume the average amount of caffeine consumed daily by adults is normally distributed with a mean of 260 mg and a standard deviation of 48 mg. In a random sample of 600 ​adults, how many consume at least 320 mg of caffeine​ daily?

In​ 2011, the mean property crime rate​ (per 100,000​ people) for 10 northeastern regions of a certain country was 2426. The standard deviation was 403. Assume the distribution of crime rates is unimodal and symmetric. What percentage of northeastern regions would you expect to have property crime rates between 1620 and 3232?

The average height of students at a university from an SRS of 14 students gave a standard deviation of 2.5 feet. Construct a 95% confidence interval for the standard deviation of the height of students at the university. Assume normality for the data.

The weight of male contestants is normally distributed with a mean of 96 kg pounds and a standard deviation of 12 kg. If 35% of contestants satisfy a maximum weight requirement for police officers, what is the maximum weight requirement?

Find the 90% confidence interval for the variance and standard deviation of the ages of students at Arcanum high school if a sample of 24 students has a standard deviation of 2.3 years. Assume the variable is normally distributed.

The length of a football field is normally distributed with a mean of 100 m and a standard deviation of 3 m. Under what size are the smallest 10% of football fields?

claim the standard deviation of pulse rates in adult women is at least 50. for a random sample of adult females the pulse rates have a standard deviation of 11.6.

A company has developed an electric car they say can travel over 500 mues on a single charge. A consumer car magazine wants to test this claim. The magazine randomly selects 16 owners of the car and ask them to measure how far the car can travel on a full charge. The mean distance traveled by these 16 cars was 510 miles with a standard deviation of 20 miles. Test the hypothesis that the mean distance the car can travel on a single charge is greater than 500 miles. Use a 0.05 level of significance. (Assume that the distances the car can travel on one charge are normally distributed.) (a) State the null and alternative hypothesis. (b) Will this be a right-tailed, left-tailed, or two-tailed test? (c) Calculate the test statistic assuming the null hypothesis is true. T = %3D (d) Use the test statistic to calculate the P-value for the test. P- value = (e) Does the data provide enough evidence to conclude that, at the 5% significance level, the mean distance this car can travel with a full…