An IQ test was given to a simple random sample of 95 students at a certain college. The sample mean score was 104.5. Scores on this test are known to have a standard deviation of $sigma = 11$. It is desired to construct a 90% confidence interval for the mean IQ score of students at this college. (4. ~ 8.) 4. What is the point estimate? (A) 99.3 (B) 100.6 (C) 104.5 (D) 105.4 5. Find the critical value. (A) 1.478 (B) 1.589 (C) 1.645 (D) 1.728 6. Find the standard error. (A) 1.1286 (B) 1.1389 (C) 1.1412 (D) 1.1455 7. Find the margin of error. (A) 1.7124 (B) 1.7657 (C) 1.8522 (D) 1.8565 8. Construct the 90% confidence interval. (A) (101.2, 105.4) (C) (102.3, 106.3) (B) (101.4, 105.9) (D) (102.6, 106.4)
Added by Stephen D.
Close
Step 1
The point estimate is the sample mean, which is given as 104.5. So the answer is (C) 104.5. Show more…
Show all steps
Your feedback will help us improve your experience
Hoan Nguyen and 98 other Intro Stats / AP Statistics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
The admissions director for a university found that (107.8, 116.2) is a 95% confidence interval for the mean IQ score of all freshmen. Is the following explanation correct, based on that information? There is a 95% probability that the interval from 107.8 to 116.2 contains x̄. Incorrect. The point estimate x̄ will always be in the center of the confidence interval, so there is a 100% chance that x̄ will be in the interval. Incorrect. If we take many samples, about 95% of them will contain the interval (107.8, 116.2) Incorrect. It should say that there is a 95% probability that the interval from 107.8 to 116.2 contains μ. Incorrect. 95% of the students at this university have an IQ between 107.8 and 116.2. Correct. That is the meaning of 95% confidence.
Robin C.
The IQ test has a mean of 100 and a standard deviation of 15. Suppose a simple random sample of 150 students take an IQ test. What is the standard error for this sample? (Round to hundredth). The national IQ test has a mean of 100 and a standard deviation of 15. Suppose a simple random sample of 150 students take an IQ test and the sample mean is 112. What is the lower bound for this 90% confidence interval level for this sample? (Round to hundredth). The national IQ test has a mean of 100 and a standard deviation of 15. Suppose a simple random sample of 150 students take an IQ test and the sample mean is 112. What is the upper bound for this 90% confidence interval level for this sample? (Round to hundredth).
Rashmi S.
-Here is a distribution of IQ scores: 74, 79, 80, 83, 83, 84, 85, 86, 86, 87, 89, 90, 90, 91, 94, 96, 97, 98, 100, 128. What is the standard deviation for this group of scores? (Note. MAKE SURE TO use formula for sample standard deviation) 10.23 74 125.68 11.21 -In the population, IQ scores are normally distributed with a mean μ = 100 and σ = 15. Using this information, answer the following questions: A. What percentage of IQ scores among the population fall between 85 and 115? B. What score identifies the top 4.95% of individuals on IQ (i.e., the 4.95% with the highest IQ)? Hint: you will need to compute z-scores and use the standard normal table to answer these questions. 34.13, 1.65 31.74, 124.75 68.26, 124.75 95, 124.75 -Say you had a sample of 100 students and computed a mean IQ of 88 with a standard error of the mean equal to 3. What would be the 95% confidence interval around the mean of 88? 85 - 115 82.12 - 93.88 85.12 - 91.65 -1.96 - 1.96 -The ___________ is the average distance that sample means are from the mean of the sampling distribution. variance standard error t-ratio F-statistic -All randomly selected samples have the exact same probability of producing a sample statistic (e.g., mean) that represents the population parameter. True or False -Which of the following best describes a probability distribution? the distribution of the frequency of occurrence of each category of a variable observed in a sample the distribution of the frequency of occurrence of each category of a variable for a population the distribution of the calculated probabilities of all possible values of a variable the probability of obtaining a sample that produced an extreme value
Paul A.
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD