Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X UI Courses x Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck 1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT f Normal Distribution. SkillsCheck1_STAT1030.pdf 4 / 10 - 80% + ... 2. Regular gas prices (in 2011$) for a sample of 5 lowa stations, in September of 2011, were 3.66, 3.63, 3.72, 3.60, and 3.58. In the following, the buying power equation, 130.74 (2011$) = 170.57 (2022$), was derived using the BLS CPI Inflation calculator 2(a) What was the average price (in 2011$) of regular gas in Sep 2011 for the sample of 5 lowa stations? 2(b) What was the standard deviation of regular gas prices (in 2011$) in Sep 2011 for the sample of 5 lowa stations? 2(c) What was the 90 percentile of regular gas prices (in 2011$) in Sep 2011 for the sample of 5 lowa stations? 2(d) What was the average inflation-adjusted (to 2022$) price of regular gas in Sep 2011 for the sample of 5 lowa stations? Hint. Each of the 5 adjusted prices will be based on the buying-power equation. 2(e) The average price of regular gas in lowa on July 27, 2022, was $4.00. Compare the price of gas in 2022 (i.e., $4.00) to the average inflation-adjusted (to 2022$) price of gas in 2011 of part 2(d). Specifically, give the inflation-adjusted percent change in regular gas price from Sep 2011 to July 2022; that is, compute " " 2022.price - avg(2011.adjusted.prices) x 100%." avg(2011.adjusted.prices) Type here to search O X 12:04 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X WI Course S X | Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck 1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT f Normal Distribution.. SkillsCheck1_STAT1030.pdf 5 / 10 - 80% + ... 3. Jim's bone density measure corresponds to a z-score of -1.75 with respect to a reference population of bone density measures for healthy 18 to 25 year old men. Denote this reference population of values by X: P and assume dist (X: P) is bell-shaped. 3(a) Interpret Jim's z-score: 3(b) About what fraction of the bone density measures in the reference population are less than or equal to Jim's? Show your work. 4. According to a manufacturer of baseballs, the weights of baseballs in a warehouse have a bell-shaped distribution with mean 5.125 oz., and about 50% of the baseballs have weights between 5.075 and 5.175 oz. What is the approximate standard deviation of the weights of baseballs in the warehouse? Show your work 5. A manufacturer of ball-bearings claims that it has a box filled with 500 ball-bearings that have diameters with mean 5 mm and standard deviation 0.02 mm. This manufacturer claims that the distribution of these 500 diameters is bell-shaped 5(a) What is the approximate 99th percentile of these diameters (at least to the 4th decimal place)? 5(b) To meet specifications, the diameter must be between 4.99 and 5.01 mm. About how many (the number, not the proportion) of the 500 ball-bearings meet specifications? Type here to search O O X 12:05 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X UI Courses x Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT f Normal Distribution. SkillsCheck1_STAT1030.pdf 6 / 10 - 80% + ... 6. A observational study of house selling prices found that an increase of one bathroom was associated with a $52,450 increase in predicted (or average) sales price. That is, for whatever reason, homes with more bathrooms sold for higher prices; specifically, a one bathroom increase is, for whatever reason, associated with a $52450 increase in predicted selling price. True or False: This study suggests that if you add a bathroom to your house its selling price is expected to increase by $52,450. A. True B. False 7. Upon release, prisoners are randomly assigned to treatment (X = 1) or control (X = 0). "Treatment" releasees will receive $500, medical prescriptions for one year, and will be assigned a case worker. "Control" releasees are simply released as usual. Whether the releasee subsequently lands back in prison within the next two years will be recorded. True or False: This is a Randomized Designed Experiment (RDE) A. True B. False 8. A random sample of 500 college graduates is taken and a random sample of 500 non college graduates is taken. Each person in the two samples is given an aptitude test. The goal of this study is to determine whether college helps people score higher on the aptitude test. True or False: Because this is an Observational Study (OS), the test results (the data) are not useful for addressing this goal. A. True B. False 9. Sales were climbing for seven years straight and were at record levels. Company leaders decided to seize the moment and update the package design. Sales then fell for the next three years. True or False: The data tells us that the package re-design caused the sales to fall. A. True B. False 10. Let RE, = "roll the six-sided die" and let T = "total number of dots on the up-faces." 10(a) Describe the process T: RE, (3) in the words of the problem. 10(b) List the collection of all possible outcomes of process T: RE, (3). 10(c) Which outcome of T: RE, (3) is more likely, 10 or 18? Type here to search O X 12:05 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X UI Courses x X Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck 1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON WI MY UI OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT fm Normal Distribution. SkillsCheck1_STAT1030.pdf 7 / 10 - 80% + ... 11. Let (X, Y):S be the return rates (%) on two stocks A and B over the past 10 years. A few of the summary statistics are: x = mean(X: s) = 5, Sx = sd(X: S) = 3, y = mean(Y:s) = 8, sy = sd(Y:s) = 10, and r = corr(X, Y:S) = -0.8. The return rate on a portfolio made up of a x 100% of Stock A and (1 - a) x 100% of Stock B is R = ax + (1 -a)Y . Suppose the portfolio is made up of 75% Stock A and 25% Stock B. Compute the expected return and volatility for the portfolio. That is, for R = 0.75 X + 0.25 Y .. 11(a) Compute mean(R:s) 11(b) Compute the "volatility" as measured by sd(R: s) (Show your work.) Type here to search O X 12:05 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X WI Courses X | Que pie X C Chegg S X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck1_STAT1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI ) OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT fm Normal Distribution. SkillsCheck1_STAT1030.pdf 8 / 10 80% ... 12. A local store collected data over a period of 10 weeks in its home consumer electronics sections. Each week they recorded the total number of sales people scheduled to work (X) and total sales, in $1000s (Y). The data can be found in salesforce_sales_exercise.xisx on ICON (see the Data Module). A scatterplot shows the relationship between sales force (X) and sales (Y) is linear over the sample s. 12(a) Compute the sample correlation r. 12(b) Compute and interpret r2. 12(c) Compute and interpret the slope of the LSQ line (regress Y on X). Make sure to use a reasonable X increment. 12(d) What weeks, if any, had residuals outside that range from -3 to +3? 12(e) Suppose 9 sales people are scheduled for next week. Give a point prediction for the sales amount. 12(f) Suppose 9 sales people are scheduled for next week, compute and interpret an approximate 95% prediction interval for the sales amount. Type here to search O X 12:09 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X UI Courses X | Que pie X C Chegg S X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON WI MY UI OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT f Normal Distribution. SkillsCheck1_STAT1030.pdf 9 / 10 - 80% + ... 12(g). Varna has used the corporate standard algorithm to decide to staff 9 sales people next week. Varna assumes that for the observed data (X, Y): s the same algorithm was used to decide on the size of the sales force (X values). Under this assumption, Varna then knows by the regression analysis above that a reasonable prediction for sales next week is Y(9), the value of the LSQ line evaluated at 9. And a easonable approximate 95% prediction interval is as calculated in part (f). Varna's boss, Kris, after seeing the regression analysis results, decides to increase the number of sales people from 9 to 19. This way, Kris reasons, they can expect 10b ($1000) more in sales, where b is the slope you found in part (c). Kris continues..Moreover, by increasing the sales force to 19, the predicted sales becomes Y(19), which, compared to Y(9), represents a nice increase in sales, especially given the $12-per-hour wages Kris pays a sales person! Varna is unsure about her boss' reasoning, but cannot articulate why. For this part (g), articulate why Varna's boss' (i.e., Kris's) reasoning is incorrect. 9 Type here to search O X 12:10 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X WI Courses x Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck1_STAT1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI ) OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT fi Normal Distribution.. SkillsCheck1_STAT1030.pdf 10 / 10 - 80% + ... 13. A grocer looked over 8000 receipts to analyze the association between the purchase of Chips and Beer. If the association is strong enough, the grocer will create a specialty display combining the two products. Let X = Chips (no = "not purchased" or yes = "purchased") and Y = Beer (no, yes). The grocer found for the sample s of 8000 receipts, FREQ Y = Beer ( X, Y ) : S ~ (n = 8000) no yes no 4750 250 X = Chips yes 2450 550 13(a) What fraction of receipts included a purchase of beer? 13(b) Of those receipts with a purchase of chips, what fraction included a purchase of beer? 13(c) Create a clearly labeled side-by-side 100% stacked bar chart for comparing the two conditional distributions dist(Y: s|X = no) and dist(Y: s|X = yes). You can draw this by hand if you wish, or use Excel. 13(d) Compute and interpret the LIFT to the purchase of beer, owing to the purchase of chips, for this sample S. Hint: See exercises at the end of lecture L3.1. -- end Skills Check #1 - 10 Type here to search O X 12:10 PM 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X WI Course S X Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON UI MY UI ) OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT f Normal Distribution.. SkillsCheck1_STAT1030.pdf 2 / 10 - 80% + ... 1. A recent government report gave farm sizes (acres) in Kossuth County, lowa. The number of farms in each of the four bins [0, 100], (100, 600], (600, 1000], and (1000, 2000], were respectively, 440, 550, 176, and 181. For example, there were 550 farms in the bin (100, 600]; i.e., 550 of the farms in Kossuth were of size greater than 100 acres and less than or equal to 600 acres. 1(a) Create a FREQUENCY histogram using the four bins. (You can draw this by hand starting with the axis below.) 0 100 600 1000 2000 1(b) Create a DENSITY histogram using the four bins. (You can draw this by hand starting with the axis below.) 100 600 1000 2000 1(c) Which histogram, FREQUENCY or DENSITY, should be used to communicate the distribution of farm size in Kossuth county? Why? Type here to search O X 12:04 PM O 9/30/2022Mail - OF X O C1 X SkillsChe X M Pulse Sur X Course R X Ap Shopping X Assignm X WI Course S X | Que pie X C Chegg S( X * [Solved] x X - C D @ File | C:/Users/reeto/Downloads/SkillsCheck 1_STAT 1030.pdf Q E X R AIR Update M GMAIL TRANSLATE ICON WI MY UI ) OFFICE 365 @ YOUTUBE N NETFLIX COURSE HERO ! SPANISH DICT fm Normal Distribution.. SkillsCheck1_STAT1030.pdf 3 / 10 - 80% + ... 1(d) The mean farm size in Kossuth is 441 acres and the standard deviation is 486. Which of the following is the median farm size in Kossuth? A. 312 B. 441 C. 495 D. 753 E. 927 1(e) What is a "typical" farm size in Kossuth? See an appropriate histogram and report a reasonable mode. 1(f) To numerically describe the distribution of farm size in Kossuth, which summary should be used? A. 2-Number B. 5-Number C. Neither, because the distribution is clearly bi-modal 1(g) What is the total farm acreage in Kossuth county? Hint: The mean farm size is 441 acres. And how many farms are there in Kossuth? .. Type here to search O X 12:04 PM 9/30/2022