stats sem 1 midterm review

Height, in meters, is measured for each person in a sample. After the data are collected, all the height measurements are converted from meters to centimeters by multiplying each measurement by 100. Which of the following statistics will remain the same for both units of measure?

• The mean of the height measurements

• The median of the height measurements

• c. The standard deviation of the height measurements

• d. The maximum of the height measurements

• e. The z-scores of the height measurements.

Height, in meters, is measured for each person in a sample. After the data are collected, all the height measurements are converted from meters to centimeters by multiplying each measurement by 100. If the shape of the original distribution is unimodal and symmetric, what will be the shape of the transformed distribution?

• unimodal and symmetric

• bell shaped

• Normal

• approximately Normal

• not enough information

A candy company produced individually wrapped candies. The quality control manager for the company believes the weight of the candies is approximately normally distributed with mean 720 mg. Assume that the manager’s assumption is correct. Which of the following intervals will contain the largest proportion of candies in the distribution of weights?

• 740 mg to 780 mg

• 700 mg to 740 mg

• 680 mg to 720 mg

• 660 mg to 700 mg

• 620 mg to 660 mg

The amount of time required for each of 100 mice to navigate through a maze was recorded. The histogram shows the distribution of times, in seconds, for the 100 mice Which of the following is closest to the standard deviation of the 100 times?

• 2.5 sec

• 10 sec

• 20 sec

• 50 sec

• 90 sec

A graph of the selling prices of homes in a certain city for the month of April reveals that the distribution is skewed to the left. Which of the following conclusions is most reasonable?

• a. The mean is greater than the median

• b. The median is the average of the first and third quartile

• c. There are fewer selling prices between the first quartile and median than there are between the median and the third quartile.

• d. There are more selling prices that are less than the mean than selling prices that are greater than the mean.

• e. The value of the maximum minus the third quartile is less than the value of first quartile minus the minimum.

If a distribution is symmetric, which of the following statements must be true?

• The distribution is Normal

• The distribution is uniform

• the distribution is bimodal

• the mean is equal to the median

• the IQR is equal to the standard deviation

The number of hurricanes reaching the East Coast of the USA was recorded for each of the last 10 decades by the National Hurricane Center. The 5 number summary is:

Min=12

Q1=15

Median=16

Q3=18

Max=24

Which of the following statments is true?

• a. The smallest observation is 12 and it is an outlier. No other observations in the data set could be outliers.

• b. The largest observation is 24 and it is an outlier. No other observations in the data set could be outliers.

• c. Both 12 and 24 are outliers. It is possible that there are other outliers.

• d. 12 is an outlier and it is possible that there are other outliers at the low end of the data set. There are no outliers on the high end of the data set.

• e. 24 is an outlier and it is possible that there are other outliers at the high end of the data set. There are no outliers on the low end of the data set.

An experiment will be conducted to determine whether children learn their multiplication facts better by practicing with flash cards or by practicing on a computer. Children who volunteer for the experiment will be randomly assigned to one of the two treatments. Because the children’s gender may affect the outcome, there will be blocking by gender. After practice, the children will be given a test on their multiplication facts. Why will it be impossible to conduct a double-blind experiment?

• a. The experimenter will know whether the child is a boy or a girl and whether he or she used flash cards or the computer.

• b. The child will know whether he or she is a boy or a girl

• c. The child will know whether he or she used flash cards or the computer.

• d. The person who grades the test will know whether the child was a boy or a girl.

• e. The person who grades the tests will know whether the child used flash cards or the computer.

An experiment will be conducted to determine whether children learn their multiplication facts better by practicing with flash cards or by practicing on a computer. Children who volunteer for the experiment will be randomly assigned to one of the two treatments. Because the children’s gender may affect the outcome, there will be blocking by gender. After practice, the children will be given a test on their multiplication facts.

Which of the following is correct?

• a. the explanatory variable is gender and the response variable is test score

• b. the explanatory variable is practice method and the response variable is test score

• c. the explanatory variable is test score and the response variable is practice method

• d. the explanatory variable is test score and the response variable is gender

• e. the explanatory variable is gender and the response variable is practice method.

An experiment will be conducted to determine whether children learn their multiplication facts better by practicing with flash cards or by practicing on a computer. Children who volunteer for the experiment will be randomly assigned to one of the two treatments. Because the children’s gender may affect the outcome, there will be blocking by gender. After practice, the children will be given a test on their multiplication facts.

Which of the following is correct?

• a. Since this is an experiment, a cause-effect conclusion is appropriate

• b. Since this is an experiment, a cause-effect conclusion is NOT appropriate

• c. Since this is an experiment, we can generalize the results to all children

• d. Because the experiment uses volunteers, we should not make a cause-effect conclusion.

• e. Because the experiment uses volunteers, we should not make a cause-effect conclusion, but we can generalize these results to all children.