A community college Math instructor feels that the average age of community college students decreased since they started teaching 25 years ago.  Looking up data from the year the instructor started teaching, the mean age of community college students was 24.3 years old, with a population standard deviation of 2.2 years.  The Math instructor took a sample of 40 of their current community college students and found that the sample had a mean age of 23.7 years old.  Assume the population of ages of community college students is normally distributed and that the population standard deviation has remained the same. Test at the 5% significance level if the mean age of community college students is now less than 24.3 years old.   The question is attached.

A study reported on essential organic molecules and a Normal model can be used to describe these levels in adults. If the mean is 194 mg/dL and a standard deviation is 28​, complete the following questions.   a) Draw and label the Normal model.   ​b) What percent of adults do you expect to have this essential organic​ molecule, cholesterol, levels over 210 mg/dL?   ​c) What percent of adults do you expect to have cholesterol levels between 150 and 170 ​mg/dL?   ​d) Estimate the interquartile range of cholesterol levels.   IQR=___________mg/dL   e) Above what value are the highest​ 15% of​ adults' cholesterol​ levels?   ___________​mg/dL

If this​ 3-year-old boy grows up to be a man with a height at the same​ percentile, what will his height​ be? Use a population mean of 70 inches and a population standard deviation of 3 inches

According to the U.S. Census, the average adult woman is the United States is 65 inches tall and the standard deviation is 3 inches.  If Zsike is 67 inches tall, what is her z-score?

The average McDonald's restaurant generates $2.4 million in sales each year with a standard deviation of 0.7. Carissa wants to know if the average sales generated by McDonald's restaurants in New Mexico is different than the worldwide average. She surveys 18 restaurants in New Mexico and finds the following data (in millions of dollars): 2.1, 2, 2.9, 1.7, 1.8, 2.3, 2.1, 2.1, 3.3, 1.4, 1.6, 1.4, 1.4, 2.3, 2.6, 2.7, 2.7, 1.7 Perform a hypothesis test using a 8% level of significance. Step 1: State the null and alternative hypotheses. Ho: pv 2.4 Ha: Ev 2.4 (So we will be performing a two-tailed test.) Step 2: Assuming the null hypothesis is true, determine the features of the distribution of point estimates using the Central Limit Theorem. By the Central Limit Theorem, we know that the point estimates are normally distributed v with and distribution standard deviation distribution mean Step 3: Find the p-value of the point estimate. P(zv [ p-value = Step 4: Make a Conclusion About the…

The U.S. Center for Disease Control reports that in year 1900, the mean life expectancy is 47.6 years for whites and 33 years for nonwhites. (Click here for reference data) Suppose a survey of randomly selected death records for white and nonwhite people born in 1900 from a certain county is conducted. Of the 110 whites surveyed, the mean life span was 48.2 years with a standard deviation of 11.2 years and of the 95 nonwhites, the mean life span was 39.3 years with a standard deviation of 16 years. Conduct a hypothesis test at the 0.05 level of significance to determine whether there was no difference in mean life spans in the county for whites and nonwhites in year 1900. Preliminary: Is it safe to assume thatnw≤5% of all white people born in 1900 andnnw≤5% of all nonwhite people born in 1900? No Yes Is nw≥30 and nnw≥30 ? No Yes   Test the claim: Determine the null and alternative hypotheses. H0: μw      μnw Ha: μw      μnw  Determine the test statistic. Round to four…

Español Valley College and Elm College are two local colleges. For each college, the distribution of the ages of faculty members is clearly bell-shaped. The ages of faculty members at Valley College have a population mean of 51 years and a standard deviation of 6.3 years. The ages of faculty members at Elm College have a population mean of 56 years and a standard deviation of 4.2 years. Maria is 67 years old and a faculty member at Valley College. Salma is 40 years old and a faculty member at Elm College. (a) Find the z-scores of Maria's age as a faculty member at Valley College and Salma's age as a faculty member at Elm College. Round your answers to two decimal places. z-score of Maria's age: z-score of Salma's age: (b) Relative to her population, who is the older faculty member? Choose the best answer based on the z-scores of the two ages. O Maria O Salma O It is unclear who is the older faculty member relative to her population Explanation 2022 Mc X Terms of Use | Privacy Center |…

As reported in Runner's World magazine, the times of the finishers in the New York City 10- km run are normally distributed with mean 61 minutes and standard deviation 9 minutes. The 75th percentile for the finishing times is 67 minutes. What is the interpretation of this value?

The income of trainess at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150.  What percentage of trainees earn less than $900 a month?

A developmental psychologist is interested in studying how long babies gaze at a photograph of a human face. To test this question, she shows a picture to a sample of six babies and records the length of their gaze in seconds. The data are as follows: 12, 17, 18, 20, 20, 29. Calculate the mean, median, mode, range, variance and standard deviation for the sample.