Stat Reasoning - Test 5

A radio station in a small town asks listeners to call in and answer the question, “Do you think that the town needs a new parking lot near the downtown shopping district?” Two hundred and sixteen people respond, and 75% of them support the idea. Is this good evidence that the majority of townsfolk support the additional parking lot?

• Yes—such a high percentage suggests widespread support for the parking lot.

• Yes-this is a random sample

• Perhaps not—this is a voluntary response sample

• a. Perhaps not—two hundred people is too small a sample for really convincing evidence.

You wish to choose a simple random sample of 4 individuals from a population of 75. You assign numbers from 01 to 75 to the individuals in the population, and use the line below from a table of random digits to select the sample. Which of the following lists of numbers represent the individuals that you will include in the sample?

Random digits:

03814 40312 57889 00095 32863 29485 82226 90056

• 03, 81, 44, 12

• 03, 14, 40, 31

• 03, 44, 12, 03

• 03, 44, 12, 57

The actual proportion of people in Happy Valley who support Gim E. Powers for mayor is 56%. A television station polls 80 randomly selected people by telephone and finds that 53% of them support Candidate Powers. Which of the following is true?

• 56% is a parameter and 53% is a statistic

• 53% is a parameter and 56% is a statistic

• Both 53% and 56% are parameters

• Both 53% and 56% are statistics

Which of the following is not a source of bias in sample surveys?

• Non-respsonse

• Voluntary response

• Wording of questions

• All of the above are sources of bias

A school newspaper is conducting a “Best film of 2015” poll. In order to adequately represent the opinions of all grade levels, the editors divide the students into 9^th, 10^th, 11^th, 12^th and sample 10% of the students in each grade level. Students in each grade are assigned a number and students’ numbers are selected using a table of random digits. This is an example of what type of sample:

• Simple Random Sample

• Stratified Random Sample

• Convenience Sample

• Cluster Sample

A recent study was conducted to see if a soy-protein powder would be effective in increasing bone density in 200 randomly selected women aged 60 to 75 who live in Canada. Which of the following represents the population?

• The 200 women

• All people in the world

• The soy-protein powder

• All women who are between the ages 60-75 in Canada

A table of random numbers is used to select 30 students from a large college statistics class to rate a statistics video. These 30 students are:

• Population

• Simple Random Sample of class

• Censu

• Voluntary response

A high school principal wants to find out how students feel about the quality of food in the school’s cafeteria. He devises a system to randomly select students as they wait in the cafeteria line at lunchtime and ask them to fill out a questionnaire about the food. Unfortunately, about 25% of the senior class leaves the school grounds to eat elsewhere each day. What is likely to be the impact of this?

• The principal’s study will be biased towards positive reviews of the food because of the response error.

• The principal’s study will be biased towards positive reviews of the food because of undercoverage

• The principal’s study will be biased towards positive reviews of the food because of nonresponse

• The principal’s study will be biased towards positive reviews of the food because of overcoverage

The student newspaper runs a weekly question that readers can answer online or by campus mail. One question was “Do you think the college is doing enough to provide student parking?” Of the 136 people who responded, 79% said “No.” The number 79% is a:

• Statistic

• Parameter

• Reliability

• Margin of error

Random samples of size n are selected from a population. What happens to the margin of error if the sample size n changes from 100 to 400?

• Remains same

• Gets smaller

• Gets larger

• Sample size and MOE are unrelated