Questions
1. What is the 95% CI for the difference between the mean starting salaries of those...

1. What is the 95% CI for the difference between the mean starting salaries of those who stay at least three years and those who leave before 3 years?  Can you say that you are 95% sure there is a difference?

Case Study: Employee Retention at D&Y
Employee Starting Salary On Road Pct State Univ CIS Degree Stayed 3 Years Tenure
1 38900 57% Yes Yes No 11
2 42300 68% Yes Yes No 5
3 39800 75% No Yes No 21
4 35700 29% No Yes Yes
5 40400 71% No Yes No 19
6 36400 62% No Yes No 18
7 37300 41% Yes No Yes
8 36600 37% No Yes No 17
9 34600 65% No Yes No 20
10 42300 53% Yes Yes No 16
11 37800 73% No Yes Yes
12 39700 60% No Yes No 12
13 36100 56% Yes Yes Yes
14 36100 42% Yes Yes Yes
15 33800 35% No Yes Yes
16 38900 36% No Yes Yes
17 35500 50% No Yes No 15
18 37600 58% No Yes Yes
19 38100 78% Yes Yes Yes
20 38300 16% No No Yes
21 34600 29% No Yes Yes
22 36300 26% No Yes Yes
23 37200 59% Yes Yes No 14
24 37700 55% Yes Yes Yes
25 36600 45% No Yes No 13
26 41000 81% Yes Yes No 9
27 40800 111% Yes Yes No 7
28 36700 56% Yes Yes Yes
29 37700 56% No Yes No 22
30 37700 42% No Yes No 11
31 39300 69% Yes Yes No 16
32 37500 50% No Yes No 18
33 40000 69% Yes Yes No 9
34 41500 64% Yes No No 5
35 39600 72% No Yes No 18
36 36900 42% No Yes Yes
37 39500 62% No Yes No 5
38 37800 20% No Yes No 23
39 38600 57% No Yes No 8
40 40600 70% Yes Yes Yes
41 41600 63% Yes Yes Yes
42 40800 44% No No Yes
43 36200 68% No Yes No 31
44 39600 59% No Yes No 10
45 36100 56% Yes Yes Yes
46 36100 42% No Yes Yes
47 39500 53% Yes Yes No 17
48 39100 38% No Yes Yes
49 40300 53% Yes Yes Yes
50 38800 78% Yes Yes Yes
51 39400 34% Yes Yes No 27
52 38400 23% No Yes Yes
53 35200 33% No Yes Yes
54 36100 24% No No Yes
55 37100 44% No Yes Yes
56 37200 64% Yes Yes No 23
57 36800 46% Yes No Yes
58 36500 27% No No Yes
59 35900 29% No No Yes
60 37900 76% Yes Yes No 14
61 37900 58% No Yes No 26
62 37900 28% No Yes No 14
63 36700 37% No Yes Yes
64 37400 49% No Yes No 19
65 38200 62% Yes Yes Yes
66 36600 51% Yes Yes No 7

In: Math

Calculate PART A PART B PART C: PART A:   If n=14, ¯xx¯(x-bar)=50, and s=9, construct a...

Calculate PART A PART B PART C:

PART A:   If n=14, ¯xx¯(x-bar)=50, and s=9, construct a confidence interval at a 99% confidence level. Assume the data came from a normally distributed population.

Give your answers to one decimal place.

< μμ <

PART B:

In a survey, 23 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $10. Find the margin of error at a 80% confidence level.

Give your answer to two decimal places.

PART C:

If n=28, ¯xx¯(x-bar)=31, and s=4, find the margin of error at a 90% confidence level

Give your answer to two decimal places.

In: Statistics and Probability

Neurofibromatosis Type 1 (NF1) is a human genetic disorder. As well as physical symptoms, affected children...

Neurofibromatosis Type 1 (NF1) is a human genetic disorder. As well as physical symptoms, affected children often suffer from impaired cognition and learning. A cognitive task that involves solving a puzzle is administered to a group of children. For each child the time taken (in seconds) to solve the task is recorded.

It is not known whether there is any suitable parametric model for the times so we will investigate non-parametric methods.


1. Calculate appropriate summary statistics and thus give the parameters for a normal distribution that may be applicable to these data.

2. Using the observed data, calculate the empirical distribution function. Plot the empirical distribution function and the CDF of the normal distribution described in (a) on a single graph.

3. Do you think the normal distribution is an appropriate model for the data? Justify your answer.

It is known that the mean time to solve the puzzle in healthy control children is 60 seconds.

The data for the observed times ?? taken by 57 children with NF1 are:

ID yi
1 51
2 60
3 75
4 43
5 92
6 72
7 49
8 39
9 62
10 127
11 51
12 75
13 69
14 59
15 25
16 58
17 95
18 63
19 91
20 63
21 32
22 50
23 108
24 41
25 93
26 43
27 74
28 50
29 55
30 60
31 62
32 91
33 79
34 71
35 85
36 86
37 78
38 100
39 146
40 62
41 134
42 41
43 40
44 51
45 68
46 59
47 59
48 38
49 66
50 79
51 111
52 69
53 68
54 110
55 69
56 62
57 91

In: Statistics and Probability

A company lost all but $50 of its inventory in a fire on Feb. 22, 2017....

A company lost all but $50 of its inventory in a fire on Feb. 22, 2017. The company’s financial records are listed below:

2015                       2016                   

Net Sales                     10,000                      12,300                   

COGS                           6,500                        7,995                   

       Gross Profit                  3,500                        4,305                   

       Operating Exp.             2,000                        2,500                   

       Net Income                   1,500                        1,805                   

              For 2017 the company’s records showed beginning inventory of $350, purchases of $500 and purchase returns of $90.  

        Net sales for the first part of the year totaled $1,000.

    

      Determine the amount of inventory destroyed in the fire. (You must first calculate the company’s historical gross profit percentage.)

A.

  $240
B.

  $360
C.

$ 60  
D.

  $150        
E.

  $110

In: Accounting

Find the sample mean and sample standard deviation of your data. What is the Z score?...

  1. Find the sample mean and sample standard deviation of your data.
  2. What is the Z score?

Data

1

223

2

200

3

154

4

217

5

223

6

157

7

178

8

159

9

350

10

243

11

325

12

298
  1. Pick three bills from the last 12 months and change the values into z-scores. What does the z-score tell you about that particular month?
  1. Between what two values would be considered a normal bill? Remember, being within 2 Standard Deviations is considered normal.
  2. Are any of your bills in the last 12 months unusual? Very unusual?
  3. Are there times when you would accept an "unusual" bill? Explain.

In: Statistics and Probability

Four important measurements were taken in harsh environmental conditions. Two of the four measurements were lost...

Four important measurements were taken in harsh environmental conditions. Two of the four measurements were lost in the harsh conditions and the remaining two are

5       3

However a scientist recalls the mean and variance of the four measurements were 6 and 20/3, respectively. Find the two missing measurements.

In: Math

7-10 The consolidate balance sheets for Loyd Lumber Company at the beginning and end of 2015...

7-10 The consolidate balance sheets for Loyd Lumber Company at the beginning and end of 2015 w follow. The company bought $50 million worth of fixed assets. The charge for depreciation in 2015 was $10 million. Net income was $33 million and the company paid put $5 million in dividends.

You must show the computations of each exercise in order to evaluate all the steps you took to reach the final result.

a- Fill in the amount of the source or use the appropriate column

b- Prepare a statement of cash flows.

c- Briefly summarize your findings.

Jan 1

Dec 31

Source

Use

cash

$7

$15

Marketable securities

0

11

Net receivables

30

22

Inventories

53

75

Total current assets

$ 90

$123

Gross fixed assets

75

125

Less: Accumulated depreciation

(25)

(35)

Net fixed assets

$50

$90

Total assets

$140

$213

Accounts payable

$18

$15

Notes payable

3

15

Other current liabilities

15

7

Long-term debt

8

24

Total liabilities

$44

$61

Common stock

29

57

Retained earnings

67

95

Total liabilities and equity

$140

$213

In: Finance

Forty percent of a firm’s employees are men. Suppose Four of the firm’s employees are randomly...

Forty percent of a firm’s employees are men. Suppose Four of the firm’s employees are randomly selected.

a. What is more likely, finding three men and one woman or two men and two women?

_The probabilities of finding three men and one woman and two men and two women are the same.

_Finding two men and two women are more likely.

_Finding three men and one woman is more likely.

b. Do you obtain the same answer as in part an if 50% of the firm’s employees had been men?

_Yes finding two men and two women is more likely.

_No finding two men and two women is more likely.

_Yes finding three men and one woman is more likely.

_Yes the probabilities of finding three men and one woman and two men and two women are the same.

In: Statistics and Probability

You are going up an elevator to reach the top of the Stratosphere casino in Las...

You are going up an elevator to reach the top of the Stratosphere casino in Las Vegas. The elevator has a mass of 900 kg. It initially starts accelerates, while moving upwards with an initial velocity of 10 m/s until it comes to rest at a height of 40 m. You have a mass of 50 kg.
a) Draw two FBD one of the elevator and one of you in the elevator. [4 points]
b) Determine the Tension force of the cable on the elevator. [6 points]
c) Determine the magnitude of the normal force you feel from the elevator [2 points]
d) Is the normal force the same as your weight? Why or why not

In: Physics

1. (a) List the sample space in the experiment "roll two dice - a red die...

1. (a) List the sample space in the experiment "roll two dice - a red die and a white die." (Hint: Use a table)

(b) Find the probability that the sum of the numbers on the two dice is less than seven.

(c) Find the probability that the sum of the numbers on the two dice is odd.

In: Statistics and Probability