Blog

A study was done by Sananman and Lear in the 1960s to monitor the amount of iron (mg/L) in the water in the Chesapeake Bay. They compared the amount of iron from a depth of 0 feet (group 1) to a depth of 30 feet (group 2). The researchers were interested in determining if the amount of iron was different at the two depths. The 95% confidence interval to compare the two depths is (-0.008, 0.0028). Interpret the confidence interval.    We are 95% confident that  . . .

A nutritionist was interested in determining if participating in a weight loss program could reduce someone’s weight. She had 4 participants participate in a medical diet plan. She recorded their weight at the beginning of the program and at the end of the program. Find the 95% confidence interval for the population mean change in weight. 1 2 3 4 before 190 210 200 210 after 170 199 197 205  

An instructor was interested in studying students satisfactory solving of a math problem. The students were given a math problem to solve before and after instruction. Each time, the student was given either a “S” for satisfactory completion or “U” for unsatisfactory completion. Two hundred randomly selected students were involved in the study. “S” after instruction “U” after instruction “S” before instruction 103 18 “U” before instruction 8 71 Besides random sampling and categorical data, what other assumption needs to be met? Is it met?

Researchers want to determine if there is a connection between choice of musical instruments and gender. They want to see if the proportion of men (m) who play the saxophone is more than the proportion of women (f) who play the flute.What would be the correct alternative hypothesis?

In 2010 and 2012, Gallup asked the same 50 people how many hours had they worked at a job in the past 7 days. Is there a difference in the population mean amount of hours worked at a job between 2010 and 2012? Would this be an example of independent or dependent samples?

An education specialist was studying SAT verbal scores at a local university. She found the following 95% confidence interval for the population mean score for SAT verbal: (450, 550). She also conducted a significance test at Ho: mu = 475 versus Ha: mu does not equal 475. The p-value for this test was 0.14.  Which of the following statements accurately describes this situation?

An education specialist was studying SAT verbal scores at a local university. She found the following 95% confidence interval for the population mean score for SAT verbal: (450, 550).   She also conducted a significance test at Ho: mu = 445 versus Ha: mu does not equal 445. The p-value for this test was 0.0007. Which of the following statements accurately describes this situation?

A nutritionist was interested in studying American’s opinions about healthy living. One hundred randomly selected people who were starting a diet were asked if they consumed at least 24 ounces of water a day. After six months, the same 100 people were asked if they consumed at least 24 ounces of water a day   Six months later “Yes, consumed at least 24 ounces of water” Six months later “No, did not” Initial Response “Yes, consumed at least 24 ounces of water” 60 20 Initial Response “No did not” 5 15  Besides random sampling, what other assumption needs to be met? Is it met?

A nutritionist was interested in studying American’s opinions about healthy eating. One hundred randomly selected people who were starting a diet whre asked if they ate three servings of whole grains a day. After six months, the same 100 people were asked if they ate three servings of whole grains a day. Besides random sampling and categorical data, what other assumption needs to be met? Is it met?   Six months later “Yes, ate whole grains” Six months later “No, did not” Initial Response “Yes, ate whole grains” 36 15 Initial Response “No did not” 7 42

Suppose that you have the following hypothesis: Ho: