TRUE/FALSE:
- The 5-number summary displays both measures of center and spread for a data set.
- When constructing a histogram, the width of each class should be the same.
- If the distribution is skewed right, then the median should be larger than the mean.
- IQR, range and mode are measures of spread.
- The standard deviation of a data set can be positive or negative.
- A parameter is a numerical measurement from a sample.
- The 68-95-99.7 rule can be applied to any distribution.
- Suppose Joe’s height among his classmates has a z-score of -2.55. It is indicates his height is 2.55 standard deviations below the mean which means he is very tall.
FILL IN THE BLANK.
- The symbol for sample mean is __________.
- The symbol for population mean is __________.
- The symbol for population standard deviation is __________.
- The symbol for sample standard deviation is _________.
- The symbol representing “the boundary separating the lowest 25% and upper 75% of data” is
SHORT ANSWER PORTION:
- In 2006, Consumer Reports published an article evaluating refrigerators. It listed 41 models, giving the brand, cost, size (cu. Ft.), an overall rating (excellent, good, etc.) and the percentage requiring repairs over the past 5 years.
- Identify the “who”.
- Identify the “when”.
- Identify the “where”.
- Identify the “why”.
- Identify all the variables and state whether each is categorical or quantitative. If categorical, determine whether the variable is nominal or ordinal. If quantitative, include the units if possible.
- Students in a political science class were asked to describe their politics as “Liberal,” “Moderate,” or “Conservative.” The results are in the table below. Show your fraction and then round the percentages to one decimal place.
- What percent of the class is male?
- What percent of the class considers themselves to be “Conservative”?
- What percent of the males in the class consider themselves to be “Conservative”?
- What percent of all students in the class are males who consider themselves to be “Conservative”?
- What’s the percent distribution of politics?
- What’s the conditional distribution of gender under the “Liberal” label?
- What’s the percent marginal distribution of gender?
- Are sex and political association independent?
- Pew Research conducted a poll from Dec. 1 to 4, 2016 which surveyed 1,320 Americans 18 years of age or older. They were asked: How much confusion do you believe fake news is sowing? They could answer: A great deal of confusion, some confusion, not much/none. The results are below:
reference: http://www.journalism.org/2016/12/15/many-americans-believe-fake-news-is-sowing-confusion/
- Identify the sample.
- Identify the population.
- Identify the variable.
- What percent of the participants believe fake news causes some confusion?
- About how many participants said believe fake news causes some confusion?
- Summarize the results of the bar chart in 2 – 3 sentences.
- Below are math scores from a recent comprehensive test from a calculus class.
- Identify the individuals.
- Identify the variable.
- Describe the spread of the distribution using interquartile range and standard deviation.
- Describe the center of the distribution using the appropriate measures in the table? Does it matter which measure we use? Explain.
- Describe the distribution in a few sentences. Make sure you comment on the overall shape, the center and spread of the distribution with appropriate numerical measures as well as possible outliers.
- Adult U.S. women have head circumferences that are normally distributed with a mean of 22.65 inches and standard deviation of 1.09 inches.
- List the population:
- List the variable:
- Express the distribution symbolically.
- Find the percentage of women that have head circumference greater than 24.75 in.
- What percentage of women have head circumferences between 21 and 23 inches?
- Find the head circumference that separates the lowest 7.25%.
- What head circumferences bound the middle 60% of U.S. women?
- The scatterplot shows speed (in mph) of winning horses each year.
- Identify the response and explanatory variables.
- What kind of relationship does the scatterplot reveal for these two variables? Describe the direction, strength and form.
- Suppose the correlation value is 0.814. Is this correlation value meaningful? Explain.