Just not getting this!
Multiple Choice Strategy: Some students have suggested that if you have to guess on a multiple-choice question, you should always choose C. Carl, the student, wants to investigate this theory. He is able to get a sample of past tests and quizzes from various teachers. In this sample there are 80 multiple-choice questions with four options (A, B, C, D). The distribution of correct answers from this sample is given in the frequency table below.
Correct | ||
Answer | Frequency | |
A | 14 | |
B | 18 | |
C | 33 | |
D | 15 | |
(a) If the correct answers for all multiple-choice problems are
uniformly distributed across the four options (A, B, C,
D), what is the theoretical proportion of those which should
have the answer C? Express your answer as an exact
decimal, not a percentage.
(b) Based on the sample that Carl collected, what is the point
estimate for the proportion of all multiple-choice questions with a
correct answer of C? Round your answer to 3
decimal places.
(c) Construct the 99% confidence interval for the proportion of
all multiple-choice questions with a correct
answer of C? Round your answers to 3 decimal
places.
< p <
(d) Can Carl be 99% confident that the correct answer of C
shows up more frequently than the theoretical value found in part
(a) would suggest?
No, because 0.25 is within the confidence interval limits. Yes, because 0.25 is below the lower limit of the confidence interval. No, because 0.25 is below the lower limit of the confidence interval. Yes, because 0.25 is within the confidence interval limits.
Ans:
a)0.25
b)Point estimate of proportion for C=33/80=0.413
c) 99% confidence interval for the proportion
=0.413+/-2.576*sqrt(0.413*(1-0.413)/80)
=0.413+/-0.142
=(0.271, 0.555)
0.271< p <0.555
d) Yes, because 0.25 is below the lower limit of the confidence interval.
Just not getting this! Multiple Choice Strategy: Some students have suggested that if you have to...
Are you likely to purchase an item promoted by a celebrity on a social media site? According to a survey, 26% of social media users have made such a purchase. Complete parts (a) through (d) below. a. Suppose that the survey had a sample size of nequals1000. Construct a 90 % confidence interval estimate for the population proportion of social media users that have purchased an item promoted by a celebrity on a social media site. nothingless than or equalspiless...
Answers to Multiple-Choice Problems: A student wants to see if the correct answers to multiple choice problems are evenly distributed. She heard a rumor that if you don't know the answer, you should always pick C . In a sample of 100 multiple-choice questions from prior tests and quizzes, the distribution of correct answers are given in the table below. In all of these questions, there were four options {A, B, C, D}. Correct Answers (n = 100) A B ...
q9 The number of successes and the sample size for a simple random sample from a population are given. a. Determine the sample proportion. b. Decide whether using the one-proportion z-interval procedure is appropriate. c. If appropriate, use the one-proportion z-interval procedure to find the confidence interval at the specified confidence level. x= 120, n= 200, 99% level a. What is the sample proportion? b. Is the one-proportion z-interval procedure appropriate? O A. O B. Yes, because x or n-x...
A manufacturing process produces steel rods in batches of 2,600. The firm believes that the percent of defective items generated by this process is 51% a. Calculate the centerline, the upper control limit (UCL), and the lower control limit (LCL) for the p chart. (Round your answers to 3 decimal places.) Centerline Upper Control Limit Lower Control Limit b. An engineer inspects the next batch of 2,600 steel rods and finds that 6.2% are defective. Is the manufacturing process under...
ch 12 q 3 Hi! the second example shows the entire qestion to the first problem, please answer the first question with those steps. :-) The number of successes and the sample size for a simple random sample from a population are given. a. Determine the sample proportion. b. Decide whether using the one-proportion z-interval procedure is appropriate. c. If appropriate, use the one-proportion z-interval procedure to find the confidence interval at the specified confidence level. x= 175, n= 250,...
For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding. In a random sample of 530 judges, it was found that 289 were introverts. (a) Let p represent the proportion of all judges who are introverts. Find a point estimate for p. (Round your answer to four decimal places.) (b) Find a 99% confidence interval for p. (Round your answers to two decimal places.) lower limit upper limit (c)...
A random sample of 320 medical doctors showed that 180 had a solo practice. (a) Let p represent the proportion of all medical doctors who have a solo practice. Find a point estimate for p. (Use 3 decimal places.) (b) Find a 98% confidence interval for p. (Use 3 decimal places.) lower limit upper limit Give a brief explanation of the meaning of the interval. 98% of the all confidence intervals would include the true proportion of physicians with solo...
A manufacturing process produces steel rods in batches of 1,500. The firm believes that the percent of defective items generated by this process is 4.8%. a. Calculate the centerline, the upper control limit (UCL), and the lower control limit (LCL) for the p chart. (Round your answers to 3 decimal places.) Centerline Upper Control Limit Lower Control Limit b. An engineer inspects the next batch of 1,500 steel rods and finds that 6.3% are defective. Is the manufacturing process under...
ILL UPVOTE 100%!!!!!! Potato Bruises A sample of 150 potatos were spot checked for bruises. "Yes" indicates that there were visible bruises. Yes To determine the total number of "Yes" answers, use =countif(select data in column A, "Yes") Yes To determine the total number of "No" answers, use =countif(select data in column A, "No") Yes Yes x--the number of bruised potatos Yes n--sample size (total number of potatos checked) Yes point estimate (pbar)--x/n Yes z--use = - norm.s.inv((1-confidence level)/2) Yes...
A student wants to see if the correct answers to multiple choice problems are evenly distributed. She heard a rumor that if you don't know the answer, you should always pick C. In a sample of 78 multiple-choice questions from prior tests and quizzes, the distribution of correct answers are given in the table below. In all of these questions, there were four options {A, B, C, D}. Correct Answer A B C D Count 16 12 18 32 Test...