Business statistics

 

 

 

 

 

 

Although experts disagree on the exact statistics, the rate of failure for new small businesses is significant. Also, even for established small businesses, the risks to success and survival are great and constantly changing in today’s market conditions. Using the information already presented in the course and resources similar to those below, we are asking you to compose a paper expressing what you believe to be the three greatest dangers to a small business and how you would address those problems as a small business owner/manager.

Instructions:

Describe and discuss the dangers of small businesses.
Identify the top three reasons YOU think small businesses struggle.
State your reasoning behind your selection of the issues.
Present your ideas for dealing with those issues.

Confidence interval for the population mean

 

The weekty time (in hours) spent doing homework for 18 randomly selected high school students is listed below.
12.0 11.3 13.5 11.7 12.0 13.0 15.5 10.8 12.5 12.3 14.0 9.5 8.8 10.0 12.8 15.0 11.8 13.0
a. Construct a 99% confidence interval for the population mean. (Assume the times ore normally distributed). Interpret you results. (Round to the nearest 1000″)
b. Find the sample mean and the sample standard deviation.
c. Repeat port a. now knowing that a = 1.8 minutes.

 

 

 

The mean age of all students enrolled in a college

An admissions director wants to estimate the mean age of all students enrolled in a college. The estimate must be within .75 of a year of the population mean. Assume the population of ages is normally distributed.
Determine the minimum sample size required to construct a 95% confidence interval for the population mean. Assume the population standard deviation is 1.5 years.

 

The critical value

 

 

1. Find the critical value ze necessary to construct a confidence interval at the level of confidence, c. Round to the nearest 1001^.
o. c = 0.86 b. c = 0.92
2. Find the margin of error for the values. Round to the nearest 1000th:
c = 0.95 a = 5.7 n = 40
3. Use the confidence interval to find the morgin of error and the sample mean:
(21.61, 30.15)

Statistical Concepts

1) IQ scores tend to be fairly stable over time. This is because IQ tests have high:
a) Validity
b) Reliability
c) Measurement error
d) Cultural fairness

2) IQ scores correlate highly with academic performance. This is an example of IQ test:
a) Validity
b) Reliability
c) Discrimination
d) Parallelism

3) Knowing a test’s standard error of measurement tells us:
a) The likelihood of scoring errors
b) How test taker distractibility distorts responses
c) The likelihood that test takers will answer questions incorrectly
d) How many points test scores are likely to vary over time

4) Dr. Hathaway writes the following statement in a test report: “Jennifer’s Verbal Comprehension Index of 102 is slightly higher than her Perceptual Organization Index of 99. This difference reflects slightly stronger verbal than non-verbal skills.” This statement:
a) Accurately describes a significant VCI/POI difference
b) Is inaccurate because the score difference is non-significant
c) Is accurate because the non-significant VCI/POI difference is described as “slight.”
d) Is inaccurate because the VCI is above average, the POI is below average, and thus the difference is not “slight.”

5) Jose’s WRAT-IV Spelling score is significantly higher than his Word Reading score, at a 5% level of significance. This means that:
a) Only 5% of the population has a difference between these scores at least as large as Jose’s
b) There is a 95% chance that Jose’s Spelling score will still be higher than Word Reading if Jose is retested
c) There is a 5% chance that the Spelling/Word Reading difference is due to test error
d) Both b and c

6) Convert a WAIS-IV IQ (Mean = 100, s = 15) of 95 to a z-score:
a) -0.05
b) -0.33
c) -0.95
d) 6.33

7) A z-score of 0.5 is at what percentile?
a) 25th
b) 50th
c) 69th
d) 84th

8) Abdul obtains a score of 13 on the WAIS-IV Block Design test. If this is the only information that you have, your best estimate of his IQ would be:
a) 87
b) 113
c) 115
d) 130

9) Someone who obtains a T-score of 60 on the MMPI-II Depression scale is scoring higher than what percent of the population?
a) 60%
b) 70%
c) 80%
d) 84%

10) Factor analysis is:
a) A statistical method that shows how variables cluster, based on the correlations between them
b) A modern form of psychoanalysis
c) A way to determine if group means are significantly different
d) A way to draw causal inferences from correlations between variables

Impact statistics as indicators of potential staffing discrimination

 

Would it be desirable to hire people only according to the person/organization match, ignoring the person/job match? Explain why are why not(2.5 points)

Chapter 1:

Are some of the thirteen strategic staffing decisions more critical than others? If so, which ones? Why?
Chapter 2:

What are the limitations of disparate impact statistics as indicators of potential staffing discrimination?
Chapter 3:

What are the potential limitations and benefits of HR and staffing planning? What costs might be incurred in the process of HR and staffing planning (e.g., staff time gathering and communicating information)?

Credit Development Manager (CDM) for BostonFinance

In the last assignment, in your role as Credit Development Manager (CDM) for BostonFinance, you asked your Data Science Team (DST) to run the K-NN algorithm for K=10 and a cutoff value of 0.0001. Now, you take only the results from the K=10 with a cutoff of 0.0001 analysis and present them to your Supervisor (without discussing any of the results from the Final Cut Predictive Model or those from the K-NN analysis using the BEST K).
Tasks
1. What parallels or similarities do you see between your decision as CDM to only selectively present the results of the K=10 and a cutoff value of 0.0001 analysis and NASA’s decision to ignore the dissenting voice (Allan McDonald and Roger Boisjoly) regarding the Challenger launch (the Challenger video especially between minutes 22:00 – 28:40)?
2. What could be the underlying motivations for these two decisions described above?