Sample

A large simple random sample of people aged nineteen to thirty living in the state of Colorado was surveyed to determine which of the two MP3 players just developed by a new company was preferred. To which of the following populations can the results of this survey be safely generalized?

• Only people aged 19-30 living in CO who were in the survey

• Only people aged 19-30 living in CO

• All people living in CO

• Only people age 19-30 in the US

The probability of obtaining a head when a certain coin is flipped is about 0.65. Which of the following is closest to the probability that heads would be obtained 15 or fewer times when the coin is flipped 25 times?

• 0.14

• 0.23

• 0.37

• 0.65

The buyer for an electronics store wants to estimate the proportion of defective wireless game controllers in a shipment of 5000 controllers. A shipment consists of 200 boxes, each with 25 controllers. The buyer numbers the boxes from 1 to 200 and randomly selects 3 of the boxes to check for defects. Which type of sample is this?

• Biased random sample

• Simple random sample

• Cluster sample

• Stratified sample

Sophomore, juniors, and senior students at a high school will be surveyed regarding a potential increase in student fees. There are 3 possible responses: agree, disagree, or no opinion. A chi-square test will be conducted to see if there is an association between year and opinion. How many degrees of freedom should be used?

• 4

• 5

• 6

• 8

An environmental scientist wanted to test the null hypothesis that an antipollution device for cars is not effective. Under which of the following conditions would a Type I error be committed?

• Concluding the device is effective when it actually is not.

• Concluding the device is effective when it actually is.

• Concluding the device is not effective when it actually is not.

• Concluding the device is not effective when it actually is.

Halftime! - Mr Lochel and Mr. Evans first met in 1992 during a summer program for math geeks.

• True

• False

A random sample of 25 households from the Central School District was surveyed. In this survey, data were collected on the age of the youngest child living in each household. According to the histogram, in which interval is the median of the data located?

• 4-6

• 6-8

• 8-10

• 10-12

The National Honor Society at Central High School plans to sample a random group of 100 seniors from all high schools in the state to estimate the mean number of hours students spend on homework. A 95% confidence interval is constructed using the sample data. If the Society would like to decrease the argin of error, which step could they take?

• Increase the sample size

• Decrease the sample size

• Increase the confidence level to 99%

• Use the sample standard deviation

If choice of color is independent of age group, which of these expressions is equal to the expected number of respondents aged 30-50 who prefer green?

A local real estate magazine used the median instead of the mean when it reported the SAT Score of the average student who attends HH. A graphical display of SAT scores for HH students in strongly skewed to the right. Which of the following explains why, in this setting, the median is a more accurate measure of center than the mean?

• The mean is affected by skew, whereas the median is not

• The mean will be less than the median due to the right skew

• The median is always the preferred statistic

• The mean should only be used when data are strongly skewed left.