A medical researcher wishes to see whether the pulse rates of smokers are higher than the pulse rates of nonsmokers. Samples of 100 smokers and 100 nonsmokers are selected. The results are shown below. Smokers Nonsmokers X, = 90 X2 = 88 S1 = 5 ni = 100 S2 = 6 n2 = 100 a) Find a 99% confidence interval for the true mean difference in smokers pulse rates and nonsmokers pulse rates. b) At a = 0.05, can we conclude that the pulse rates of smokers is higher than the pulse rates on nonsmokers?

find out the confidence interval for population proportion  for given data  [ 4 decimal places ] population standard deviation =4 xbar = 123.5 sample size= 100 c= 0.95

The level of dissolved oxygen in a river indicates the water’s ability to support aquatic life. A research project is started to determine if the oxygen levels in the river have changed. A study done 10 years prior, showed that the mean oxygen levels in milligrams per liter for the river was 4.3. A.) Write appropriate hypotheses for this test B.) Water is collected samples from 15 randomly chosen locations along the river and measured the dissolved oxygen. Construct and interpret a 95% confidence interval for the mean dissolved oxygen level for this stream. The results are in milligrams per liter:  4.53 5.5 4.01 5.04 4.83 4.66 3.29 4.4 2.87 5.23 5.42 5.73 4.13 6.38 5.55 C.) Based on the sample from part B, conduct a significance test of these results using a 5% significance level. Give complete results of the test including a p-value and what the results means.

Calcium is essential to tree growth. In​ 1990, the concentration of calcium in precipitation in a certain area was 0.11milligrams per liter (mg/L).A random sample of 10 precipitation dates in 2018 results in the following data table. Complete parts​ (a) through​ (c) below. (B) With 98​% confidence, the mean concentration of calcium in precipitation in this area in 2018 is between

A researcher collected sample data for 10 women ages 18 to 24. The sample had a mean serum cholesterol level (measured in mg/100 mL) of 188.4, with a standard deviation of 5.7. Assuming that serum cholesterol levels for women ages 18 to 24 are normally distributed, find a 99% confidence interval for the mean serum cholesterol level of all women in this age group. Then find the lower limit and upper limit of the  99%  confidence interval.