In order to ensure efficient usage of a server, it is necessary to estimate the mean number of concurrent users. According to the records, the average number of concurrent users at 185 randomly selected times is 31.2, with a standard deviation σ = 3.6 Construct a 95% confidence interval for the expectation of the number of concurrent users. (Round the answer to 4 decimals)
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- The researcher took a random sample of 50 residents and found that the mean height of men is 175cm. Suppose that the team is made aware of the fact that the distribution of heights is distributed normally. 1, The sample median is an unbiased estimate of the mean height of men. Is the following statement about the estimator true? 2, Determine whether or not the median or mean is an efficient estimator of the population median.The visibility standard index (VSI) is a measure of Denver air pollution that is reported each dayto theDenver Post. The index ranges from 0 (excellent air quality) to 200 (very bad air quality).During the winter months, when air pollution is higher, the index has a mean of about 90 (rated as fair) with a standard deviation of approximately 30. Suppose that for 15 days (during the winter), the following VSI measures were recorded each day. Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 VSI 80 115 100 90 15 10 53 75 80 110 165 160 120 140 195 a) Make a control chart for the VSI, and plot the above data on the control chart. Besure to include the horizontal lines on the control chart b) identify all out-of-control signals (above or below the mean) that you find in the control chart by type (Type I, II, or III)In a survey, 29 people were asked how much they spent on their child's birthday gift. The results were roughly bell-shaped with a mean of $46.8 and standard deviation of $5.8. Estimate how much a typical parent would spend on their child's birthday gift using a 98% confidence interval. Express the answer in the format of x +- E.
- A researcher is interested in studying the use of hypnosis to relieve pain. She took a random sample of 16 subjects and measured their sensory ratings. The mean of the sensory ratings was found to be 7.5 and standard deviation to be 2.3. It is known that the sensory ratings are normally distributed. Construct a 99% confidence interval for the mean sensory ratings of the population. a) (5.81, 9.19) b) (6.27, 8.73) c) (6.36, 8.64) d) (6.02, 8.98)The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1775 pounds and a standard deviation of 60 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, μ, of the cables is now greater than 1775 pounds. To see if this is the case, 90 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1788 pounds. Can we support, at the 0.05level of significance, the claim that the population mean breaking strength of the newly-manufactured cables is greater than 1775 pounds? Assume that the population standard deviation has not changed. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. a. State the null hypothesis H0 and the alternative hyposthesis H1. b. Find the value of the test statistic. c. Find the p-value. d. Can we…At the conclusion of Eligibility examination for admission into engineering courses at military Q6 technological college, data was collected by the Bureau of statistics for the purpose of conducting different surveys. It has been found that the mean height of 800 examinees is 175 cm and standard deviation is 5cm. If we assume the heights are Normally Distributed, determine the number of examinees likely to have heights: i. More than 180cm ii. Less than 170cm iii. Between 178cm and 188
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- a sociologist found that in a sample of 45 retired men, the average number of jobs they had during theirlifetimes was 7.2. The population standard deviation is 2.3.Find the 90% confidence interval of the mean number of jobs. Round intermediate and final answers to one decimalplace.<h<A certain group of test subjects had pulse rates with a mean of 70.470.4 beats per minute and a standard deviation of 11.111.1 beats per minute. Use the range rule of thumb to identify the limits separating values that are significantly low or significantly high. Is a pulse rate of 52.652.6 beats per minute significantly low or significantly high? Significantly low values are nothing beats per minute or lower.A data set includes 31 body temperatures of healthy adult humans having a mean of 98.3°F and a standard deviation of 0.82°F. Using this sample information, a 99% confidence interval estimate of the mean body temperature is found to be (97.90° , 98.71°). What does this information suggest about the use of 98.6°F as the mean body temperature? A. Since the confidence interval does not include the mean body temperature of 98.6°F, the results suggests that the mean body temperature could not be 98.6°F. B. Since the confidence interval includes the mean body temperature of 98.6°F, the results suggests that the mean body temperature could be 98.6°F. C. Since the confidence interval includes the mean body temperature of 98.6°F, the results suggests that the mean body temperature could not be 98.6°F. D. Since the confidence interval does not include the mean body temperature of 98.6°F, the results suggests that the mean body temperature could be 98.6°F. Click to select your answer. ?
