A simple random sample from a population with a nomal distribution of 100 body temperatures has x= 98.20°F and s 0.64°F. Construct a 98% confidence interval estimate of the standard deviation of body temperature of alI healthy humans.

A sample of 20 automobiles has a pollution by-product release standard deviation of 2.5 ounces when one gallon of gasoline is used. Find the 95% confidence interval of the population variance. using chi table determine the confidence interval of the true population variance

A simple random sample from a population with a normal distribution of 98 body temperatures has x=98.40°F and s=0.68°F. Construct a 90​% confidence interval estimate of the standard deviation of body temperature of all healthy humans.

A researcher is comparing the amount of calories in two different lunch special pizzas: Hawaiian and pepperoni. Random samples of 30 Hawaiian and 30 pepperoni are taken. The mean amount of calories in the Hawaiian pizza was 800 calories with a standard deviation of 50 calories and the mean amount of calories in the pepperoni pizza was 1000 with a standard deviation of 100 calories. The population standard deviations are unknown but considered to be equal. What is the 99% confidence interval for the difference between the two population means? O Confidence Interval - (800- - 1000) ± 2.576₁ (50)² 30 Confidence Interval= (800-1000) + (2.663) (79.06, Confidence Interval=(800-1000) ± 2.663, (50) 30 Confidence Interval= (800-1000) + (2.576) (79.06. + (100)² 30 1 1 30 30 + (100)² 30 1 1 30 30 + )

The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 253.8 and a standard deviation of 61.7. What is the approximate percentage of women with platelet counts between 192.1 and 315.5?

A randomized controlled trial is run to evaluate the effectiveness of a new drug for asthma in children. A total of 250 children are randomized to either the new drug or a placebo (125 per group). The mean age of children assigned to the new drug is 12.4 with a standard deviation of 3.6 years. The mean age of children assigned to the placebo is 13.0 with a standard deviation of 4.0 years. Suppose that there are 63 boys assigned to the new drug group and 58 boys assigned to the placebo group. Is there a statistically significant difference in the proportions of boys assigned to the treatments? Run the appropriate test at a 5% level of significance.