Wheel thickness on a train is random because wear and tear causes the wheel to wear down. The distribution of wheel thickness is known to have a standard deviation of 0.52 inches. The average wheel thickness tells you how old the train is. A random sample of 22 wheels on the Brazos Express Train found an average wheel thickness of 8.29 inches. Find a 99.8% confidence interval for the true average wheel thickness on the Brazos Express. Use 4 decimal

Please help me understand the problem. Is the given standard deviations 6, and 7? I know I need to use the unit normal table, and shade the curve. But how? Thanks.

A quantitative data set has a size 50. At least how many observations lie within 3standard deviations to either side of the​ mean?

please answer the question in the photo. Thank you

Plz help asap t1.

i already have answer in question A-D. please help me to solve the rest. topic is unkown standard deviation

Pyramid Lake is on the Paiute Indian Reservation in Nevada. The lake is famous fortrout. Suppose that a friend tells you that the average length of trout caught in PyramidLake is μ = 20 inches. However, the Creel survey reported that for a random sample of 27fish caught, the mean length was 22.1 inches with a sample standard deviation of 4.3inches. Does this data indicate that the average length of trout caught at Pyramid Lake ismore than 20 inches? Use α = 0.05.a. State the null hypothesis. ___________ State the alternative hypothesis. ________________b. Find the test statistic. ______ c. Find the P-value for the test._____________

Please help with homework problem.

A company organizes its sales into territories, each assigned to one sales representative. An analyst theorizes that the on-the-job experience level of the sales rep may be related to the amount of sales in each territory. The analyst decided to use the time the sales reps had been employed at the company to predict sales. After taking a random sample of sales territories, the analyst measured the last quarter's Sales in dollars and the Experience the sales rep had at the company in months. Here are the three tables from the regression results: Regression Statistics Multiple R R Square Adjusted R Square Standard Error Observations ANOVA Regression Residual Total Intercept Experience (months) 0.5966 0.3559 0.339 497.9058 40 df 1 38 39 Coefficients 6.6108 SS 5205388.04 5205388.04 9420585.51 Standard Error 4250.9742 180.2332 14625973.55 1.4427 How many territories are in the sample? 247910.15 t Stat MS 23.586 4.5822 P-value 2.71E-24 4.85E-05 F 20.9971 Lower 95% Upper 95% 3886.1113…

Assume the cholesterol levels of an adult can be described by a Normal model with a mean of 183 ​mg/dL and a standard deviation of 27. Complete parts a through e.   ​b) What percent of adults do you expect to have cholesterol levels over 190 ​mg/dL?   enter your response here   ​% ​(Round to two decimal places as​ needed.) Part 3 ​c) What percent of adults do you expect to have cholesterol levels between 150 and 160 ​mg/dL?   enter your response here   ​% ​(Round to two decimal places as​ needed.) Part 4 ​d) Estimate the interquartile range of cholesterol levels.   IQR=enter your response here   ​mg/dL ​(Round to the nearest integer as​ needed.) Part 5 ​e) Above what value are the highest​ 15% of​ adults' cholesterol​ levels?   enter your response here   ​mg/dL ​(Round to the nearest integer as​ needed.)