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descriptive_statitiscs_and_interpretation.docx

Create a Microsoft® Excel® spreadsheet with the two variables from your learning team's dataset.

Analyze the data with MegaStat®, StatCrunch®, Microsoft® Excel®or other statistical tool(s), including:

(a) Descriptive stats for each numeric variable

(b) Histogram for each numeric variable

(c) Bar chart for each attribute (non numeric) variable

(d) Scatter plot if the data contains two numeric variables

Determine the appropriate descriptive statistics.

(a) For normally distributed data use the mean and standard deviation.

(b) For significantly skewed data use the median and interquartile range.

Use the Individual Methodology Findings Template to complete the descriptive statistics. Use the Descriptive Statistics and Interpretation Example to develop an interpretation of the descriptive statistics.

Format your paper consistent with APA guidelines.

Submit both the spreadsheet and the completed Individual Methodology Findings Template.

Click the Assignment Files tab to submit your assignment.

TEMPLATE

Descriptive Statistics

Determine the appropriate descriptive statistics.

Note: If the data was normally distributed, use the mean and standard deviation. If the data was skewed significantly, use the median and interquartile range.

Numeric Variable Name1

Distribution: State if not normally distributed

Central Tendency:

Dispersion:

Number:

Min/Max:

Confidence Interval: (if distribution is normal)

Numeric Variable Name2 (if applicable)

Distribution: State if not normally distributed

Central Tendency:

Dispersion:

Number:

Min/Max:

Confidence Interval: (if distribution is normal)

Attribute Variable Name (if applicable)

Create a bar chart. Describe the proportions.

Descriptive Statistics Interpretation

Numeric Variable Name1

Describe the variable in laymen terms.

Numeric Variable Name2 (if applicable)

Describe the variable in laymen terms.

EXAMPLE

University of Phoenix Material

Descriptive Statistics and Interpretation Example

Interpretation Phrases

Central Tendency:

Mean = average of a set of data

Median = half or equal number of data is above and half or equal number of data is below. It is a midpoint in an ordered (sorted) set of data, a physical location

Mode = most frequent value in a set of data

Dispersion:

Standard deviation = variation

Interquartile range (IQR) = the middle 50% of the data

Range = the difference between the largest and smallest value of the data

Confidence Interval: (data must be normal)

There is 95% confidence that the population average is between _____ and ____ units.

Normal or significantly skewed data:

MegaStat: Descriptive statistics Normal curve goodness of fit p-value

· Normal, p-value > .05

· Significantly Skewed, p-value < .05

Histogram: Eyeball the histogram.

· Normal data will have a symmetrical or slightly skewed shape.

· Significantly Skewed shape will have extreme skewness

Use phrase combinations: Normally distributed: Mean and Standard Deviation, Not normally distributed: Median and IQR

Descriptive Statistics

Body Weight (Lbs.)

Central Tendency:

Mean = 149 Lbs.

Dispersion:

Standard deviation = 30 Lbs.

Count:

100

Min/Max:

99 pounds and 234 Lbs.

Confidence Interval:

144 to 155 Lbs.

See the histogram in Appendix A, and descriptive statistics in Appendix B.

Age

Distribution is not normally distributed

Central Tendency:

Median = 36 years

Dispersion:

Interquartile Range = 20.5 years / 2 = ± 10 years

Count:

100

Min/Max:

18 years and 74 years

Confidence Interval:

Not applicable (data is not normally distributed)

See the histogram in Appendix A, and descriptive statistics in Appendix B. A scatter plot is in Appendix C.

Education Level

Thirteen percent of the subjects have no high school degree while 44% have high school degree. Forty three percent have a college or college graduate degree. See the bar chart in Appendix D.

Descriptive Statistics Interpretation

Interpretation

Body Weight

One hundred subjects were randomly selected. Their body weight was observed between 99 and 234 pounds. Their average weight was 149 pounds, with a variation of plus or minus 30 pounds. One half or more were above 149 pounds. There is 95% confidence that the population body weight average is between 144 and 155 pounds.

Age

The data was significantly skewed. One hundred subjects were randomly selected. Their ages were between 18 and 74 years, with a variation of plus or minus 10 years. One half or more subjects were 36 years of age or older. The middle half of the subjects’ ages fell between 27 and 47 years. The most frequent age was 36 years.

APPENDIX A

Body Weight and Age Histograms

APPENDIX B

Descriptive Statistics Body Weight and Age

APPENDIX C

Scatterplot Body Age versus Weight

APPENDIX D

Bar Chart Education Level

Data Sets

The following chart shows the driving trend for Virginia from 2004 to 2014. The population for this data is licensed drivers. The sampling is alcohol related incidents for the past 11 years. The target population is all drivers that are of drinking age which is 21 years of age and older. However, the data provided does not include a breakout for underage drinkers. Further data is required in order to make a correlation between raising the alcohol tax rate and alcohol related incidents. As noted in the chart below, the number of incidents has decreased in the past 11 years. This consideration will also need to be included to determine if in fact there is a probability that the number of alcohol incidents will decrease by increasing the alcohol tax.

Note: Data extracted from the 2014 edition of Virginia Traffic Crash Facts.

From 2007 to 2013 Virginia’s tax rate per gallon has steadily increased with the exception of 2013 when tax rates decreased. These rate increases are a result of inflation and not targeted excise tax increases by the state. Recognizing Virginia is third in the nation when taxing spirits (namely liquor) it is also important to note Virginia is 31st in the nation when comparing tax rates for beer (Center for Science in the Public Interest).

(Tax Foundation, 2013)

When determining the correlation between drunken driving accidents and increases in alcohol tax rates first it must be determined if there are actual tax increases to compare the data. Using the proposed November 2014 increase in “case handling fees”, which raised the cost of an average bottle sold in Virginia by 20 cents, research can then be established to compare drunken driving crashes to any change in the number drunken driving accidents. As well as, whether the numbers increase or decrease as a direct correlation with the increase in costs in Virginia.

Reference

Center for Science in the Public Interest. (n.d.). States Ranked By Alcohol Tax Rates: Beer. Retrieved June 07, 2015, from cpsinet.org

Tax Foundation. (2013, April). State Excise Rates on Spirits, 2007-2013. Retrieved June 07, 2015, from Tax Foundation: taxfoundation.org/article/state-excise-tax-rates-2007-2013

Virginia Highway Safety Office. (2014). 2014 Virginia Traffic Crash Facts. Retrieved from

https://www.dmv.virginia.gov/safety/crash_data/crash_facts/crash_facts_14.pdf

Virginia Driving Trends

Alcohol Related

Crashes

2004 2005 2006 207 2008 2009 2010 2011 2012 2013 2014 11504 11495 11736 11215 10294 9366 8217 8411 8776 8047 7666

Year

Occurrences

Virginia Alcohol Tax Rate 2007-2013

Tax Rate 2007 2009 2010 2011 2013 14.54 19 20.13000000000001 20.91 20.56