BST322 Week 4 Discussion 2

Module 5 Measures of Dispersion Name Course and Year Exercise 5.1 Determine the sample variance and standard deviation for the following data. CI F 10-14 5 15-19 20 20-24 35 25-29 25 30-34 15 Total 100

A sports shop selects a random sample and records the sales of items made in China and thosemade in America. Country of origin n mean St.Deviation           China 50 22.5 9.75           America 33 33.15 11.6                             What is the SE Mean for the sales from China?

K The first statistics exam had a mean of 71 and a standard deviation of 15 points; the second had a mean of 82 and a standard deviation of 5 points. Anna scored a 84 on both tests. Megan scored 94 on the first exam and 74 on the second. They both totaled 168 points on the two exams, but Anna claims that her total is better. Explain. The total of Anna's z-scores is, which is greater than Megantotal of (Round to one decimal place as needed.)

The reliability of an estimator is assessed in terms of its _____. Select one: a. mean  b. ease of computation c. coefficient of variation d. variance

2. Which of following statement is NOT correct about standard error? a. the square root of the estimated variance of coefficient is called standard error b. standard error is a measure of the relative precision of the estimate c. larger value indicate more uncertainty about the estimated coefficient d. none of above

Given the following data .Find the OLS estimators using the deviation method. Y 6 10 9 14 7 5   X1 1 3 2 -2 3 5   X2 3 -1 4 6 2 4

2 The sample variance is _______. a 8285.94     b 9469.64     c 10521.83     d 11690.92

2) You work for the FTC. A manufacturer of detergent claims that the mean weight of detergent is at least 6.5 lb. You take a random sample of 64 containers. You calculate the sample average to be 6.43 lb. with a standard deviation of .14 lb. At the 0.02 level of significance, is the manufacturer correct?

..is the best measure of dispersion. .. Select one: Range a. b. Variance Standard Deviation C.

In your own words, describe what the difference is between an error term and a residual. How does sample size affect the variance of each?

Calculate SP (the sum of products of deviations) for the following scores, Note: Bothmeans are decimal values, so the computational formula works well.X Y0 41 10 54 12 11 3

p The Graduate Management Admission Test (GMAT) is a standardized exam used by many universities as part of the assessment for admission to graduate study in business. The average GMAT score is 547 (Magoosh website). Assume that GMAT scores are bell-shaped with a standard deviation of 100. Use the empirical rule to answer the following. a. What percentage of GMAT scores are 647 or higher (to 1 decimal)? % b. What percentage of GMAT scores are 747 or higher (to 1 decimal)? c. What percentage of GMAT scores are between 447 and 547 (to 1 decimal)? d. What percentage of GMAT scores are between 347 and 647 (to 1 decimal)?

What do you mean by Sample Variance, Sample Standard Deviation,and Standard Error?

The covariance by itself is not very useful because ___________.

2. Below is the estimated demand function for high-class tea (cups per month). Variable Estimated Coefficient Standard Error Constant  0.22 0.034 Price of high-class tea (in $100) -1.43 0.521 Income level (in $1000) 0.86 0.186 Being male 3.29 2.179 Sample Size 3624 3624 (a) For individual with income of $40000, he or she is found to consume 22 cups permonth. Based on the estimation result above, compute and comment on the incomeelasticity for high-class tea. (b) According to the result, would males drink more high-class tea? Explain. (c) If you add the price of coffee into the demand analysis, what would you expect onthe sign and significance of the price of coffee variable for the case of a rise in theprice of coffee? Explain. While you are not required to provide computation orexample, please use a demand-supply diagram for the market for tea to illustrate your expectation.

A large milling machine produces steel rods to certain specifications. The machine is considered to be running normally if the standard deviation of the diameter of the rods is at most 0.42 millimeters. The line supervisor needs to test the machine is for normal functionality. The quality inspector takes a sample of 45 rods and finds that the sample standard deviation is 0.49. What is the test statistic? Select one: а. 59.89 b. 48.63 с. 50.50 d. 52.45

b(Y)=400Y-6Y2 c(Y)=5y2

Economic topic. Show your work A weighing machine without any display was used by an average of 320 persons a day with a standard deviation of 50 persons. When an attractive display was used on the machine, the average for 100 days increased by 15 persons. Can we say that the display did not help much? Use a level of significance of 0.05?

19 The mean of z-scores in a data set       a is zero only when the x-values are balanced around the mean of x. b is greater than zero for data sets that have large outlying values. c is always equal to one.         d is always equal to zero

If the t-statistic for a variable is -1.74, is the variable statistically significant? O No O Yes

12 A researcher reports survey results by stating that the margin of error for the 95% middle interval of the sample means is 44.75.  The population variance is assumed to be σ² = 18750.  The sample size used in this survey is ________.     a 53               b 44               c 36               d 31

Please no written by hand and no emage A way to measure uncertainty of outcome is (choose only one answer): Betting market prices Win percentages Standard deviation of win percentages HHI of championship teams

MEAN ABSOLUTE DEVIATION Q.1) Find the mean absolute deviation for the set below. S = {85, 90, 68, 75, 79} A. В. C. D. 79.4 6.48 32.4 79 Sherrie just registered for her wedding. So far 6 items have been fulfilled on her registry. Find the Q.2) mean price of the fulfilled items. $29, $58, $15, $129, $75, $22 43.5 129 54.7 114 А. В. С. D. Find the mean absolute deviation of the fulfilled items on Sherrie's registry. $29 , $58, $15, $129, Q.3) $75, $22 196 54.7 114 32.67 C. D.

P0 = R130; Ps = R 100; Pm = R200; Q1 = 1000; Q0 = 1200 a) Calculate supplier’s revenue before tax and  after tax.  b) Calculate the total tax revenue collected by the government.  c) Calculate the total tax paid by the consumers and total tax paid by the suppliers.  d)Compare the results inc above and give a logical explanation for the variance

ou would like to get the highest paying job possible after graduating from UCR and are currently deciding vhether to enroll in ECON 108 in the fall term or not. You find a sample of recent UCR graduates that majc n Economics (there are no double majors in the samples). You sampled 100 Economics majors that took ECON 108 and you find that the average starting salary is 72K dollars, with a sample standard deviation of 10K dollars. You sampled 75 Economics majors that did not take ECON 108 and you find that the average starting salary is 65K dollars, with a sample standard deviation of 15K dollars. Which of the following statements is most correct? O I am not very confident in the results of my hypothesis test because the range in which I fail to reject the null hypothesis is relatively large. O I want to be very confident in the results of my hypothesis test, so the range in which I fail to reject the null hypothesis is relatively large. O The range in which I fail to reject is small, so…

SCCoast, an Internet provider in the Southeast, developed the following frequency distribution on the age of Internet users. Find the mean and the standard deviation. (Round squared deviations to nearest whole number and final answer to 2 decimal places.)   Age (years) Frequency 10 up to 20   3   20 up to 30   7   30 up to 40   18   40 up to 50   20   50 up to 60   12

Shack Homebuilders Limited is evaluating a new promotional campaign that could increase home sales. Possible outcomes and probabilities of the outcomes are shown next. Possible Outcomes Ineffective campaign Normal response Extremely effective Additional Sales in Coefficient of variation Units 50 70 130 Probabilities 0.40 0.30 0.30 Compute the coefficient of variation. Note: Do not round intermediate calculations. Round your answer to 3 decimal places.

QUESTION 8 Having an extreme score in a sample (outliers) will NOT effect which of the following?     standard deviation     mean     mode     variance

Question of the day. The mean weekly sales of the chocolate bar in candy stores was 146-3 bars per store. After an advertising campaign the mean weekly sales in 22 stores for a typical week increased to 153-7 and showed a standard deviation of 17-2. Was the advertising campaign successful?

Use the following STATA output to test whether the variable wgt is significant at 5% level: Source | SS df Number of obs = EC 3. Prob > F R-squared MS 392 300.76 0.0000 0.6993 Adj R-squared anba6970 4.2965 388) = Model Juu16656.4443 Residual 162,54916 5552.1481 388 18.4601782 Total Juu23818.9935 391 60.9181419 Root MSE Coef. Std. Err. P>It| [95% Conf. Interval] syl ena wat .2677968 -.012674 -.0057079 44.37096 .4130673 .0082501 .0007139 1.480685 -0.65 -1.54 -8.00 29.97 0.517 0.125 0.000 0.000 -1.079927 -.0288944 -.0071115 41.45979 .5443336 0035465 .0043043 47.28213 _cons The variable is not significant because p-value is less than 0.05. The variable is significant because p-value is less than 0.05. The variable is significant because p-value is less than 0.1. The variable is not significant because p-value is greater than 0.05

A a measure of the uncertainty associated with a parameter estimate that results from sampling variation is referred to as the standard deviation. an upward bias. the standard error. the sampling variation.

Question Help Every ten years, the census bureau asks people about the number of people living within their households. The following list shows how eight households responded to the question. 3 6 6. 3 9. 4 4 a) Calculate the range. b) Calculate the sample variance. c) Calculate the sample standard deviation.