MCQ3 Flashcards
(15 cards)
From a random sample of 50 people, sitting pulse rates and standing pulse rates were measured for each person. A coin was flipped to determine whether the sitting or the standing pulse rate would be measured first. Let µsitting represent the mean sitting pulse rate in the population, µstanding represent the mean standing pulse rate in the population, and µd represent the mean of the differences between the sitting and standing (sitting - standing) pulse rates in the population. Which of the following represents an appropriate test and hypotheses to determine if there is a difference in mean pulse rates between sitting and standing in the population?
A matched-pairs t-test with H0 : μd = 0 and Ha : μd ≠ 0
A matched-pairs t-test is NOT an appropriate way to analyze data consisting of which of the following?
Measurements of annual income for both individuals in pairs formed by assigning 100 people to pairs at random
In a certain school, students can choose whether to eat in the school’s cafeteria. A reporter working for the school’s newspaper polled students on their reactions to changes in the menu at the cafeteria. For each student leaving the cafeteria in one 30-minute time period, the reporter used a coin to determine whether to stop the student and ask how he or she felt about the new menu. In the reporter’s article it was stated that a random sample of the students showed that 89 percent of the school’s student population was happy with the new menu. Which of the following statements is true?
Because students self-selected whether to eat in the cafeteria, the sampling method might be biased and the sample might not be representative of all students in the school.
Ms. Tucker travels through two intersections with traffic lights as she drives to the market. The traffic lights operate independently. The probability that both lights will be red when she reaches them is 0.22. The probability that the first light will be red and the second light will not be red is 0.33. What is the probability that the second light will be red when she reaches it?
0.40
The prices, in thousands of dollars, of 304 homes recently sold in a city are summarized in the histogram below.
The figure shows a histogram with the horizontal axis labeled Price, in thousands of dollars, and the left vertical axis labeled Number of Homes Sold. The horizontal axis has equally spaced tick marks labeled from 250 to 2,500 in increments of 250. The vertical axis has equally spaced tick marks labeled from zero to 140 in increments of 20. There are 9 bars on the histogram, centered between the tick marks, with the height given on the top of the bar as follows, from left to right: Bar between 250 and 500: height 38. Bar between 500 and 750: height 120. Bar between 750 and 1,000: height 82. Bar between 1,000 and 1,250: height 38. Bar between 1,250 and 1,500: height 10. Bar between 1,500 and 1,750: height 8. Bar between 1,750 and 2,000: height 5. Bar between 2,000 and 2,250: height 2. Bar between 2,250 and 2,500: height 1.
Based on the histogram, which of the following statements must be true?
The median price is not greater than $750,000.
As part of a study on the relationship between the use of tanning booths and the occurrence of skin cancer, researchers reviewed the medical records of 1,436 people. The table below summarizes tanning booth use for people in the study who did and did not have skin cancer.
A table is shown with three columns labeled used a tanning booth, did not use a tanning booth, and total. The first row is for skin cancer and reads 190, 706, and 896. The second row is for no skin cancer and reads 75, 465, and 540. The third row is for total and reads 265, 1171, and 1436.
Of the people in the study who had skin cancer, what fraction used a tanning booth?
190/896
A researcher is conducting a study of charitable donations by surveying a simple random sample of households in a certain city. The researcher wants to determine whether there is convincing statistical evidence that more than 50 percent of households in the city gave a charitable donation in the past year. Let p represent the proportion of all households in the city that gave a charitable donation in the past year. Which of the following are appropriate hypotheses for the researcher?
H0: p = 0.5 and Ha: p > 0.5
A company determines the mean and standard deviation of the number of sick days taken by its employees in one year. Which of the following is the best description of the standard deviation?
Approximately the mean distance between the number of sick days taken by individual employees and the mean number of sick days taken by all employees
A local television news station includes a viewer survey question about a current issue at the beginning of every evening news broadcast. Viewers are invited to use social media to respond to the question. The results of the survey are shared with the audience at the end of each broadcast. In relation to the opinions of the population of the region, which of the following is a possible reason why the results of such surveys could be biased?
I. Viewers with strong opinions about the current issue are more likely to respond than are viewers without strong opinions.
II. The opinions of viewers of one television station are not necessarily representative of the population of a region.
III. Viewers with access to social media are not necessarily representative of the population of a region.
I, II and III
A graduate student conducted a study of field mice in rural Kansas. The student obtained a sample of 100 field mice and recorded the weight, in grams, of each mouse. After the measurements were taken, it was discovered that the scale was not calibrated correctly. The student adjusted the 100 recorded measurements by subtracting 3 grams from each measurement. Which of the following statistics for the weight, in grams, of the field mice has the same value before and after the adjustment?
The Interquartile Range
A statistician proposed a new method for constructing a 90 percent confidence interval to estimate the median of assessed home values for homes in a large community. To test the method, the statistician will conduct a simulation by selecting 10,000 random samples of the same size from the population. For each sample, a confidence interval will be constructed using the new method. If the confidence level associated with the new method is actually 90 percent, which of the following will be captured by approximately 9,000 of the confidence intervals constructed from the simulation?
The population median
The distribution of monthly rent for one-bedroom apartments in a city is approximately normal with mean $936 and standard deviation $61. A graduate student is looking for a one-bedroom apartment and wants to pay no more than $800 in monthly rent. Of the following, which is the best estimate of the percent of one-bedroom apartments in the city with a monthly rent of at most $800 ?
1.3%
Assuming all conditions for inference were met, which of the following represents a 95 percent confidence interval for µ?
A news article reported that college students who have part-time jobs work an average of 15 hours per week. The staff of a college newspaper thought that the average might be different from 15 hours per week for their college. Data were collected on the number of hours worked per week for a random sample of students at the college who have part-time jobs. The data were used to test the hypotheses
H0: μ = 15
Ha: μ ≠ 15,
where µ is the mean number of hours worked per week for all students at the college with part-time jobs. The results of the test are shown in the table below.
A table is shown with two rows. The first row reads sample mean, standard error, d f, t stat, and p value. The second row reads 13.755, 0.707, 25, negative 1.761, and 0.090.
13.755 ± 1.456
The random variable X is normally distributed with mean 5 and standard deviation 25. The random variable Y is defined by Y = 2 + 4X. What are the mean and the standard deviation of Y ?
The mean is 22 and the standard deviation is 100.
n northwest Pennsylvania, a zoologist recorded the ages, in months, of 55 bears and whether each bear was male or female. The data are shown in the back-to-back stemplot below.
A stem and leaf plot is shown with female on the left and male on the right. Stem value 15 has leaf 4 on the left and no leaves on the right. Stem value 13 has leaves 2 and 0 on the left and no leaves on the right. Stem value 9 has leaf 4 on the left and no leaves on the right. Stem value 8 has leaf 2 on the left and no leaves on the right. Stem value 7 has leaf 1 on the left and leaf 0 on the right. Stem value 6 has leaves 1 and 0 on the left and leaf 6 on the right. Stem value 5 has leaves 8, 3, and 2 on the left, and leaves 3 and 5 on the right. Stem value 4 has leaves 6, 5, 4, 2, and 1 on the left, and leaf 6 on the right. Stem value 3 has leaves 8, 8, 5, 4, 3, and 2 on the left, and leaves 2, 4, 7, and 8 on the right. Stem value 2 has leaves 9, 7, 6, 2, 1, 0, and 0 on the left, and leaves 0, 0, 1, 2, 2, 3, 4, 4, 4, 5, 6, 7, 7, and 9 on the right. Stem value 1 has no leaves on the left and leaves 5, 7, and 8 on the right. The rest of the stem values have no leaves.
Based on the stemplot, which of the following statements is true
The median age and the range of ages are both greater for female bears than for male bears.
