Data Science, I will give thumb up, thank you

What is one critical drawback to the MLR (multiple linear regression model) model (or any MLR model) for predicting shardnado hazard? What are some modifications that could improve on this issue?

sharknado hazard: the hazard of a sharknado, where 1 is very unlikely and 100 is highly likely

1. Using the Data Set, create and calculate the following in Excel^®:

Determine the range of values in which you would expect to find the average weekly sales for the entire sales force in your company 90% of the time, and calculate the following:

A. The impact of increasing the confidence level to 95%

B. The impact of increasing the sample size to 150, assuming the same mean and standard deviation, but allowing the confidence level to remain at 90%

Data Set:

SAMPLE OF WEEKLY SALES
Sales Rep #	AverageWeekly Sales($)		Week #	Weekly Sales($) - Rep A	Weekly Sales($) - Rep B
1	1228		1	4657	5839
2	7374		2	6133	2602
3	1055		3	3438	2830
4	1859		4	7394	4763
5	3938		5	4327	3740
6	1692		6	2552	2315
7	569		7	7063	1599
8	4059		8	7844	1629
9	3689		9	6898	2416
10	607		10	4003	2107
11	1370		11	6884	4237
12	3735		12	4007	6322
13	3305		13	7214	3710
14	7228		14	2358	5890
15	6279		15	7745	5119
16	1671		16	1337	5184
17	5708		17	1052	3439
18	2569		18	6056	4828
19	4163		19	1495	3667
20	1519		20	3530	3518
21	7734		21	4749	6073
22	784		22	3833	5566
23	6766		23	7869	4555
24	7261		24	4541	5867
25	5034		25	6882	6039
26	7115		26	3868	1032
27	6291		27	5934	4834
28	6287		28	4447	3687
29	2080		29	5504	5500
30	7621		30	5554	4659
31	1047
32	6517
33	5172
34	3876
35	5429
36	4538
37	3786
38	2510
39	4863
40	7246
41	1175
42	641
43	4269
44	7034
45	3406
46	2256
47	3182
48	5178
49	4428
50	1189

A) A study is conducted to assess the relationship between the use of marijuana during pregnancy and adverse delivery outcomes, defined as major congenital malformations. The following variables are used in the analysis.

Delivery outcome: major congenital malformation versus other delivery.

Risk factors:

1. Marijuana usage during pregnancy: yes or no

2. Race: White or non-white

3. SES categorized as: low, middle, or high

4. Maternal age

5. Any previous stillbirth: yes or no

a) Write down a model to evaluate this relationship including terms in the model for the confounding factors and interactions between marijuana usage and each of the other factors. Be sure to state the coding scheme you are using to represent the variables in the model.

b) Write down the odds ratio corresponding to the model in part (a) for the odds of malformation given marijuana usage relative to the odds of malformation given no usage.

A magazine subscriber study asked, "In the past 12 months, when traveling for business, what type of airline ticket did you purchase most often?" A second question asked if the type of airline ticket purchased most often was for domestic or international travel. Sample data obtained are shown in the following table.

Type of Ticket	Type of Flight
	Domestic	International
First class	29	22
Business class	97	123
Economy class	516	133

(a)

Using a 0.05 level of significance, is the type of ticket purchased independent of the type of flight?

State the null and alternative hypotheses.

H₀: The type of ticket purchased is not independent of the type of flight.
H_a: The type of ticket purchased is independent of the type of flight.

H₀: The type of ticket purchased is independent of the type of flight.
H_a: The type of ticket purchased is not independent of the type of flight.      

H₀: The type of ticket purchased is not mutually exclusive from the type of flight.
H_a: The type of ticket purchased is mutually exclusive from the type of flight.

H₀: The type of ticket purchased is mutually exclusive from the type of flight.
H_a: The type of ticket purchased is not mutually exclusive from the type of flight.

Find the value of the test statistic. (Round your answer to three decimal places.)

Find the p-value. (Round your answer to four decimal places.)

p-value =

State your conclusion.

Reject H₀. We conclude that the the type of ticket purchased is not independent of the type of flight.

Do not reject H₀. We cannot conclude that the type of ticket purchased and the type of flight are not independent.    

Do not reject H₀. We cannot conclude that the type of ticket purchased and the type of flight are independent.

Reject H₀. We conclude that the type of ticket purchased is independent of the type of flight.

(b)

Discuss any dependence that exists between the type of ticket and type of flight.

A higher percentage of first class and business class tickets are purchased for domestic flights compared to international flights. Economy class tickets are purchased more for international flights.

The type of ticket purchased is independent of the type of flight.     

A higher percentage of first class and business class tickets are purchased for international flights compared to domestic flights. Economy class tickets are purchased more for domestic flights.

A lower percentage of economy class tickets are purchased for domestic flights compared to international flights. First class and business class tickets are purchased more for domestic flights.

1. Stephen (Steph) Curry, an American NBA player on the Golden State Warriors, led the 2018 NBA salaries with the largest payroll for the NBA. A fan looks up the salaries for all of the players on the 2018 Golden State Warriors basketball team. Because the fan took a statistics course, the fan uses all of these salaries to get a 95% confidence interval to estimate the mean salary for all 2018 Golden State Warriors basketball players. This makes no sense. Why not? (1 pts)

Music Group		Control Group
30	28	30	23
32	25	23	26
28	30	24	20
26	29	29	20
30	28	26	26
20	27	20	21
24	29	26	23
33	27	21	20
31	26	22	26
26	28	25	27
30		27

SPSS.1 A study reveals that older adults work out a little harder when they listen to music. The table below contains the data from two groups of older adults: one group listened to music while walking; the other group did not listen to music. Stride length was measured as an indicator of how hard they were working out (higher numbers = longer stride = working out harder).

What are the sample means in this study?

                                                                      M_music =                   M_control =

SPSS.2 Paste your SPSS output of the descriptive statistics below.

SPSS.3 What t statistic was obtained (calculated) for the music and exercise study.

SPSS.4 Assuming a two-tailed hypothesis test with alpha = .05, use your t-table to look up the critical t-value for this study. What are the critical t-values?

SPSS.5 What p-value is obtained from your SPSS output?

SPSS.6 Is there a statistically significant effect of music on stride length?

Here are quarterly data for the past two years, from these data, prepare a forecast for the upcoming year using decompostion. foreccast years 9 to 12. FORECAST ERROR?

Period	Actual	period	Actual
1	300	5	416
2	540	6	760
3	885	7	1191
4	580	8	760

Suppose a market analyst wants to determine whether the average price of a gallon of whole milk in Seattle is greater than Atlanta. To do so, he takes a telephone survey of 21 randomly selected consumers in Seattle who have purchased a gallon of milk and asks how much they paid for it. The analyst undertakes a similar survey in Atlanta with 18 respondents. Assume the population variance for Seattle is 0.03, the population variance for Atlanta is 0.015, and that the price of milk is normally distributed. Given average price for Seattle is $2.52, and average price for Atlanta is $2.38.

(1). Use the correct R command to compute a 99% confidence level confidence interval of the difference in the mean price of a gallon of milk between Seattle and Atlanta. (note: in the R function, you need the value of standard deviation for both samples. You need to calculate the standard deviation based on the variance, then plug the standard deviation values in the R function) What are the lower bound and upper bound of the interval?

(2). Using a 1% level of significance (alpha = 0.01), manually test whether the average price of a gallon of whole milk in Seattle is greater than Atlanta. What is the statistical decision and business decision?

(3). Using a 1% level of significance. Import data set MilkPrice_S.csv and MilkPrice_A.csv files to R studio. Write the correct R commands for testing whether the average price of a gallon of whole milk in Seattle is greater than Atlanta. What is the p value? What is the statistical decision and business decision?

Seattle
2.55
2.36
2.43
2.67
2.54
2.43
2.5
2.54
2.38
2.61
2.8
2.49
2.43
2.61
2.57
2.36
2.56
2.71
2.5
2.64
2.27 Atlanta 2.25 2.4 2.39 2.3 2.33 2.4 2.49 2.29 2.23 2.41 2.48 2.29 2.39 2.59 2.53 2.26 2.38 2.45

The manager of computer operation of a large company wants to study computer usage of two departments within the company-the accounting dept. and the research dept. A random sample of five jobs from the accounting dept. in the past week and six jobs from the research dept. in the past week are selected, and the processing time(in seconds) for each job is recorded. Use a level of significance of 0.05, 1. Please provide descriptive stat. for the data ( Excel) 2. Is there evidence that the mean processing time in the research dept. is greater 6 seconds? ( Hand calculated, but use mean and SD from Excel output) 3. Is there evidence of a difference between the mean processing times of these two depts.?(Please use Excel, then you will use hand calculation to double check your answer) For question 2 and 3, make sure that you write down H0 and H1, conclusion and summary.

Accounting 9 3 8 7 12

Research 4 13 10 9 9 6

According to Masterfoods, the company that manufactures M&M’s, 12% of peanut M&M’s are brown, 15% are yellow, 12% are red, 23% are blue, 23% are orange and 15% are green. (Round your answers to 4 decimal places where possible)

a. Compute the probability that a randomly selected peanut M&M is not red.



b. Compute the probability that a randomly selected peanut M&M is yellow or green.



c. Compute the probability that three randomly selected peanut M&M’s are all green.



d. If you randomly select five peanut M&M’s, compute that probability that none of them are orange.



e. If you randomly select five peanut M&M’s, compute that probability that at least one of them is orange.

Homework Question #1:

The Following Table shows total annual sales for 10 high-end supermarket stores and the median age of residents of each town where these stores are located. Supermarket executives believe that their store products appeal to a younger generation. (obtain all graphs and calculations from minitab, but provide all manual calculations)

Sales ($M)	5.540	10.700	10.532	5.995	5.090
Median Age	39.5	34.5	30.4	36.2	40.8
Sales ($M)	3.995	2.774	4.828	5.511	4.195
Median Age	41.5	34.7	41.4	38.0	40.0

1. Obtain a scatterplot and examine/describe the general relationship between sales and median age of the town residents
2. Do you think the linear model is appropriate? Explain
3. The marketing manager fit the regression line. What is the equation of that line? Is the regression significant? What is the R-Square value?
4. From a “Regression Analysis” report obtained from minitab, do you have any reservations about the prediction you found in (d)? Explain

Do students reduce study time in classes where they achieve a higher midterm score? In a Journal of Economic Education article (Winter 2005), Gregory Krohn and Catherine O’Connor studied student effort and performance in a class over a semester. In an intermediate macroeconomics course, they found that “students respond to higher midterm scores by reducing the number of hours they subsequently allocate to studying for the course.” Suppose that a random sample of n = 8 students who performed well on the midterm exam was taken and weekly study times before and after the exam were compared. The resulting data are given in Table 10.6. Assume that the population of all possible paired differences is normally distributed. Table 10.6 Weekly Study Time Data for Students Who Perform Well on the MidTerm Students 1 2 3 4 5 6 7 8 Before 16 13 11 17 17 13 15 17 After 8 8 12 9 5 10 7 8 Paired T-Test and CI: Study Before, Study After Paired T for Study Before - Study After N Mean StDev SE Mean StudyBefore 8 14.8750 2.2952 .8115 StudyAfter 8 8.3750 2.0659 .7304 Difference 8 6.50000 4.03556 1.42678 95% CI for mean difference: (3.12619, 9.87381) T-Test of mean difference = 0 (vs not = 0): T-Value = 4.56, P-Value = .0026 (a) Set up the null and alternative hypotheses to test whether there is a difference in the true mean study time before and after the midterm exam. H0: µd = versus Ha: µd ≠ (b) Above we present the MINITAB output for the paired differences test. Use the output and critical values to test the hypotheses at the .10, .05, and .01 level of significance. Has the true mean study time changed? (Round your answer to 2 decimal places.) t = We have evidence. (c) Use the p-value to test the hypotheses at the .10, .05, and .01 level of significance. How much evidence is there against the null hypothesis? There is against the null hypothesis.

1. As beach temperatures rise, more female turtles are born. I want to show that more than 50% of the current turtle hatchlings are female, as this further threatens the turtle population. a. Define any relevant parameters and state the null and alternative hypotheses. b. If I want a margin of error of .01, what sample size should I get? c. I check 1000 eggs and find 676 of them are female. Use StatKey to find the SE, then use that SE to find a 99% confidence interval. d. Now use the formula discussed in chapter 6 for SE and create a 95% confidence interval. e. How do these intervals compare? f. Interpret the interval in the context of the problem. g. Find the z-score using the Statkey SE. What is the resulting p-value? h. Find the z-score using the formula SE. What is this resulting p-value? i. Compare these p-values. j. What is your formal decision and conclusion with context?

In the game of​ roulette, a player can place a ​$9 bet on the number 6 and have a 1 /38 probability of winning. If the metal ball lands on 6​, the player gets to keep the ​$9 paid to play the game and the player is awarded an additional ​$315 ​Otherwise, the player is awarded nothing and the casino takes the​ player's ​$9. Find the expected value​ E(x) to the player for one play of the game. If x is the gain to a player in a game of​ chance, then​ E(x) is usually negative. This value gives the average amount per game the player can expect to lose

9.3.3

A study was conducted that measured the total brain volume (TBV) (in ) of patients that had schizophrenia and patients that are considered normal.  Table #9.3.5 contains the TBV of the normal patients and table #9.3.6 contains the TBV of schizophrenia patients ("SOCR data oct2009," 2013).  Is there enough evidence to show that the patients with schizophrenia have less TBV on average than a patient that is considered normal?  Test at the 10% level.

Table #9.3.5: Total Brain Volume (in ) of Normal Patients

1663407	1583940	1299470	1535137	1431890	1578698
1453510	1650348	1288971	1366346	1326402	1503005
1474790	1317156	1441045	1463498	1650207	1523045
1441636	1432033	1420416	1480171	1360810	1410213
1574808	1502702	1203344	1319737	1688990	1292641
1512571	1635918

Table #9.3.6: Total Brain Volume (in ) of Schizophrenia Patients

1331777	1487886	1066075	1297327	1499983	1861991
1368378	1476891	1443775	1337827	1658258	1588132
1690182	1569413	1177002	1387893	1483763	1688950
1563593	1317885	1420249	1363859	1238979	1286638
1325525	1588573	1476254	1648209	1354054	1354649
1636119