Stats review

The x^2 statistic for this test is 10.09. Which of the following gives the correct interval for the p-value of the test?

0.01<P-Value<0.02

The five number summary of test scores for the 600 students in an introductory psychology class at Enormous State University is 52 65 78 85 96. How many students scored higher than 65?

450

Choose a random shopper at a local grocery store. Let Event P= The shopper is buying some kind of fresh produce. Let Event C= The shopper is paying with a credit card. Below is a Venn Diagram of the probabilities associated with these two events Which one of the two-way tables below conveys the same information?

B C and p= 0.45, C^c and p= 0.60, p^c and C= 0.64, and p^c and c^c= 0.21

The sample mean and margin of error for the confidence interval are

Mean = 7.1; Margin of error = 1.2

Isobel takes a simple random sample of 28 seniors at her school and finds that 20 of them are planning to participate in the school's annual capture the flag game. She wants to construct a confidence interval for p=proportion of seniors who plan to participate in the game, but she realizes she hasn't met all the conditions for constructing the interval. Which condition has she failed to meet?

n(1-p̂) ≥ 10

A state park charges $3 admission for each car entering the park, plus $1 for each occupant of the car (for example, a car with four occupants would be charged $3 plus $4 or $7). Below is a probability distribution for X= the number of occupants of a randomly selected car entering the park Which of the following is the expected value for the money collected from a randomly selected car entering the park?

$6.20

Use scenario 11-5. The expected count for cell "Males/Brand B" cell is given by which of the following expressions?

(38)(18)/96

A random sample of 30 words form Jane Austen's Pride and Prejudice had a mean length of 4.08 letters with a standard deviation of 2.40. A random sample of 30 words from Henry Jame's what Maisie Knew had a mean length of 3.85 letters with a standard deviation of 2.26. Which of the following is a correct expression for the 99% confidence interval for the difference in mean word length for these two novels?

(4.08-3.85) +- ( √2.40^2+ 2.26^2/30)

The mean score on Mr. Groucher's AP Calculus test was 68.472 and the standard deviation was σ=15.4. The scores were distinctly skewed left. Ace's test score was 58. Which of the following is closest to Ace's z-score

-0.68

Jen's school bus arrives at her stop at 6:00 am. If she misses the bus, her father drives her to school. Let event B=Jen catches the bus, and F= Jen makes it to her first period class on time. The tree diagram at right summarizes the probabilities in this situation Given that Jen makes it to her first class on time, what is the probability her father drove her to school?

0.168

Select a random student at Lakeville High School. Let Event S= The student owns a smartphone, and Event T= The student sends an average of more than 50 texts per day. The Venn diagram below summarizes the probabilities associated with these two events. Which of the following is the probability that a randomly selected student does not send an average of more than 50 texts per day, given that they own a smartphone?

0.333

A marketing firm wants to estimate the proportion of people in a city who use a certain brand of mobile phone. They want to produce a 90% confidence interval with a margin of error of at most 0.07. Which of the following is the smallest sample size that will produce the desired interval?

139

A consumer electronics store sells a particular brand of protective case for smartphones in four different colors. Below is data on color preference for 76 randomly selected sales of these cases in a three-month period For the null hypothesis that the proportion of total sales for each color is the same, what is the expected cell count for "Green"

19

A psychology professor at a large university asks 100 randomly selected students majoring in the humanities and 100 randomly selected math/science majors which of the two brands of smartphone they prefer, "Brand A" or "Brand S". Here are her results: If the professor wants to determine if humanities and math/science majors differs significantly in their preferences for these two brands, which of the following tests should she use?

A z-test for the difference of two proportions and A chi-square test for homogeneity Either A. or C

Ida wants to know if males and females prefer different brands of ready-made chocolate-chip cookie dough. She bakes eight dozen cookies from dough made from each of four manufacturers which she labels brands A, B, C, and D. She then selects a simple random sample of 96 students, records their gender, gives them one cookie of each brand and asks which brand they like best. Here are her results Use scenario 11-5. The conditional distribution for preferred cookie brand among male (in percents) is given by which of the following

A: 11%, B: 16%, C: 34%, D: 39%

Which of the following statements is true of chi-square distributions

As the number of degrees of freedom increases, their density curves look less like a normal curve

If each observed count is exactly equal to each expected count in a chi-square goodness-of-fit test, then the chi-square statistic will

Equal 1

Which one of the following statements about x^2 distributions is true?

For any X^2 distribution, P(x^2 ≥ 0) = 1

Use scenario 11-10. Which of the following are appropriate null and alternative hypotheses fir these data?

H0: The distribution of favorite food group is the same for both genders HA: The distribution of favorite food group is not the same for both genders

A grocery store wants to know if a display of cranberries near the entrance to the store increases the proportion of shoppers who buy them. To determine this they first flip a coin each morning to decide whether they place the cranberries near the entrance that day or locate them in their customary place in the produce section. Then they take a random sample of shoppers for several days and calculate p̂1= the proportion of shoppers who buy cranberries when they are near the store entrance , and p̂2= the proportion of shoppers who buy cranberries when they are in their customary spot. Which of the following is a correct set of hypothesis for the appropriate test for significance?

H0: p1-p2= 0;Ha: p1-p2 > 0

Suppose you are conducting a test of significance for which H0: p=0.7. Which of the following tests against a specific alternative hypothesis has the greatest power?

Ha:P= 0.73, with n=80, and a=0.05

The two-way table below gives the chi-square components for the appropriate test on these data Based on these information which of the following statements are valid

II only

Which one of the following is the best interpretation of the 99% confidence level for the mean sugar content of the shipment

If we constructed many, many confidence intervals from independent samples of this size, 99% of the time the interval we constructed would capture the true mean

Use the following information for questions 20-22 A 99% confidence interval for the sugar content (per 5 oz. serving) of a shipment of strawberries is 5.9 to 8.3 grams If, instead of calculating a 99% confidence interval, we chose to calculate a 95% confidence interval using the same data, which of the following would describe the change in width of the interval?

It would definitely be narrower

Dogs vary in size a great deal more than cats do. Suppose the mean weight of dogs in a certain city is 28 lb and a standard deviation of 14 lb and the mean weights of all cats is 9.5 lb with a standard deviation of 2 lb. Cats weights are normally distributed but dog weights are skewed to the right. Suppose you take separate random samples of 10 dogs and 8 cats from this city. Which of the following is an accurate description of the center, spread, and shape of the sampling distribution of the difference in the mean weight dogs and the mean weight of cats?

Mean= 18.5 pounds, Standard Deviation= 4.48 pounds, shape non-Normal

Use scenario 11-10. The chi-square statistic for this test is x^2=11.239. Which if the following is the correct conclusion to draw?

Reject H0 at a=0.05; fail to reject H0 at a=0.01

Below are dot plots from five different samples. Which one of these samples does not satisfy the Large sample/Normal condition for performing one-sample t-procedures? Sample sizes: A: n=34, B: n=32; C: n=32; D: n=10; E: n=12

Sample C

Use scenario 11-5. If we want to compare the conditional distributions for preferred cookie brand among males to the same distribution for females, which of the following is an appropriate graph to use?

Side-to side histograms

The mean weight of men in the United States is 69 inches and the standard deviation is 3 inches. For U.S, women, the mean is 64 inches and the standard deviation is 2.7 inches. The tallest women in the Women's National Basketball Association is Brittney Griner, who is 80 inches tall (6 feet 8 inches) . The tallest current player in the Men's NBA is Hasheem Thabeet, who is 87 inches tall (7 feet 5 inches). Which player is taller relative to others of the same sex in the U.S.?

Thabeet, because his z-score is higher

The scatterplot below displays the relationship between carbohydrate content and protein content for 17 different 6' sandwiches at Subway. The two points on the far right (slightly larger and lighter than the others) represent the Meatball Marinara sandwich and the Applewood Pulled Pork sandwich. If these two points were removed from the data, how would the correlation and the slope of the least-squares regression line change?

The correlation would increase and the slope of the regression line would increase

Which of the following is a condition that must be satisfied to use a chi-square goodness-of-fit test?

The expected count for each category is at least 5

Which one of the following potential problems is addressed by performing a blind study

The placebo effect

In a recent poll by the Pew Research asked 856 randomly selected adults about their education level and whether or not they have a facebook account. Here are the results If we are interested whether there is a relationship between educational level and use of Facebook, which of the following is the appropriate null hypothesis

The variables "Educational Level" and "Facebook account" are independent

Below is the computer output for a least-squares regression of y= protein (in grams) and x= calories for 16 different sandwiches produced by a major sandwich franchise. Which of the following best describes what S= 5.723 represents?

The typical distance between the observed calorie content for each type of sandwich and the mean calories content is 5.723

Use scenario 11-5. The appropriate null hypothesis for Ida's question in this problem is

There is an association between gender and preferred cookie brand