11-1
At the end of the month, a restaurant manager used the total food sales for the month and the total number of customers for the month to calculate that the mean amount spent per customer during that month was $12.59. Is this value a statistic or a parameter?
Parameter
Describe the type of study method described in the situation:
A list of students is randomly generated from the school database. Information for every student is entered into the database, and each student has an equally likely chance of being selected. The students selected are asked how much time they spend on household chores each week.
Sample Survey
Identify the five-number summary of the following:
9, 13, 18, 20, 24, 31, 33, 37, 46, 50
Give your answer in ascending order
9, 18, 27.5, 37, 50
The Empirical Rule may also be called The ____________ Rule
68-95-99.7
What are the different type of hypotheses used in a hypothesis test?
Null and alternative
Describe the variable for the following statistical question: “How many hours do students spend using computers each night?”
The number of hours spent on a computer in a night
Describe the bias in the following:
To investigate a community’s reading habits, a magazine invites readers to complete and mail in a survey.
The people who respond to the survey may overrepresent the number of readers in the community
Describe the shape of the distribution and determine which measures of center and spread best represent the data.
29, 12, 24, 34, 56, 39, 42, 64, 47, 33, 50, 55, 63, 46
Approximately normal; mean; standard deviation
24,500 to 75,500
Assume the population means are to be estimated from the samples described. Find the margin of error. Round to the nearest tenth as needed.
Sample size = 169, sample mean = 75, sample standard deviation = 9
1.4
What type of variable is represented in the following question: “How many pets does your family own?” Explain why.
Quantitative; the data is numerical
Student government members survey every 5th student who enters the school building and asks whether students favor the school’s new dress code.
What type of sampling method was used?
Systematic
Determine if the situation is likely to be uniformly distributed, normally distributed, skewed left, or skewed right.
Critic scores of a critically acclaimed movie
Skewed left
A set of data has a normal distribution with a mean of 46 and a standard deviation of 8. Find the percentage of data within the following interval.
From 38 to 54
68%
Find the 95% confidence interval for the survey results described. **Hint: Calculate the margin of error (round to the nearest whole number) then find the range of values.
According to a poll of 1007 people, about one-third (34%) of Americans keep a dog for protection.
31% to 37%
During a middle school dodgeball game, every spectator placed his or her ticket stub into one of several containers. After the game, the coach chose twelve people to march in the sportsmanship parade. What is the sample in this situation?
The twelve people to march in the sportsmanship parade
A group of farmers wants to test a new fertilizer being produced for soybean crops. Explain how the farmers could set up the control group and the experimental group for this study.
The experimental group should use the new fertilizer, while the control group should use the same growing techniques that were being used before.
Determine if the situation is likely to be uniformly distributed, normally distributed, skewed left, or skewed right.
The probability of drawing each card from a deck of playing cards.
Uniformly distributed
Find the percentage of all values in a normal distribution for the following z-score. Round to the nearest tenth as needed.
z<-2.12
1.7%
Formulate the null and alternative hypothesis for a hypothesis test.
A business manager claims that greater than 85% of their employees are college graduates.
Null: p=0.85
Alternative: p>0.85
A state randomly questioned some of its high schools about the average percentages of their students who attend home football games. Describe the population and the sample for this data.
Population: High schools in the state.
Sample: List of high schools that were surveyed
A pharmaceutical company is developing a new oral medication for the treatment of psoriasis, a skin disease marked by red, itchy, scaly patches. Describe how you could design a controlled experiment to test the effects of the medication. How could you keep participants from knowing whether they were in the treatment group?
Randomly select a sample of people with psoriasis. Randomly assign them to one of two groups. Give one group the treatment, and withhold it from the other group. Give both groups similar looking pills, so neither knows which group they are in.
Describe a scenario that is likely to be normally distributed.
Several potentially correct responses
1.5
A survey found that 72% of freshmen planned to take at least one spring break trip while in college with a margin of error of 3.5%. Central U claims that 75% of freshman plan trips. Is their claim reasonable? Explain why.
Yes. Their claim is within the margin of error.