Segment Income
Excel 3.9 Test the difference in levels between alternate scenarios or pairs with a paired t test
We will test the hypothesis that the average difference between ratings of a Conventional portfolio and ratings of a Socially Desirable portfolio is greater than zero.
Open Excel 3.9 SD Portfolio.xls.
Use the Excel function TTEST(array1, array2,tails,type) to calculate a paired t test. For array1, enter the socially desirable ratings in A. For array2, enter the conventional ratings in B. For tails, enter 1 for a one-tail test, and for type, enter 1 to specify a paired t test.
Type in the label p value in C35.
In D35, enter =TTEST(A2:A34,B2:B34,1,1)[Enter]:
To see the distribution of differences between Socially Desirable and conventional portfolios in the sample add the label Socially Desirable difference in D1 and enter the possible differences -6, -5, -4, . . .4, 5, 6 in D2:D14:
Difference between Conventional and Socially Desirable Portfolio Ratings.
Excel 3.9 Test the difference in levels between alternate scenarios or pairs with a paired t test 75
Use shortcuts to order a histogram tabulation of the socially desirable differences in D.
Use shortcuts to insert a PivotTable of the tabulation.
Drag Socially Desirable difference to ROW and drag Frequency to DATA:
Double click the Sum of Frequency box and Show values as, % of total.
Reduce decimals in B, then click the PivotChart icon.
Excel 3.10 Construct a confidence interval for the difference between alternate scenarios or pairs 77
Use the mean difference in C36 and the margin of error in C38 to find the 95%
confidence interval bounds for the difference:
In C39, enter =C36-C38[Enter].
In C40, enter =C36+C38[Enter].
Excel Shortcuts at Your Fingertips
By Shortcut Key
Alt activates the shortcuts menus, linking keyboard letters to Excel menus. Press Alt, then release and press letters linked to the menus you want.
The following are examples of shortcuts. Press Alt, then
H 9 to select the Home menu and the reduce decimals function
H DC to select the Home menu and the Delete function to delete column(s)
H IC to select the Home menu and Insert function and to insert a column to the left of the selected cell or column
AY2 to select the Data and Data Analysis menus AS to select the Data and the Sort menus
NC to select the Insert function and to insert a column chart ND to select the Insert function and to insert a scatterplot NE to select the Insert function and to insert a pie chart
NVT to select the Insert function, the Pivot menu, and to insert a PivotTable NX to select the Insert function and to insert a text box
WFR to select the View and Freeze panes menus, and to Freeze rows JAB to select the Layout and Data Labels menus
JARM to select the Layout, the Error Bar, and the custom Error Bar menus Shift+arrow selects cells scrolled over
Cntl+C to copy
Cntl+down arrow scrolls through all cells in the same column that contain data and stops at the last filled cell.
Cntl+R fills in values of empty cells using a formula from the first cell in a selected array Cntl+Shift+down arrow selects all filled cells in the column.
Excel Shortcuts at Your Fingertips 79
By Goal
If you want to
Activate shortcuts menus, press Alt, then release.
Add data labels in a column chart: select a column, then Alt JAB Add error bars in a column chart: select a column, then Alt JARM Analyze data: Alt AY2
Copy cells: select the cells, then Cntl+C Delete a column: Alt HDC
Freeze the top row: Alt WFR Insert a column: Alt HIC Insert a column chart: Alt NC Insert a pie chart: Alt NE Insert a PivotTable: Alt NVT Insert a row: Alt HIR Insert a scatterplot: Alt ND Insert a text box: Alt NX
Move to the end of a column: Cntl+down arrow Reduce decimals: Alt H9
Select all of the filled cells in a column: select the first cell in the column, then Cntl+Shift+down arrow
Sort data: Alt AS
Lab Practice 3 Inference
cingular’s Position in the Cell Phone Service Market
cingular’s managers have conducted a survey of customers in 21 major metropolitan areas to assess the quality of service along three key areas: coverage, absence of dropped calls, and static. Customers rated cingular service along each of these three dimensions using a five-point scale (1=poor to 5=excellent). Data are in Lab Practice 3 cingular.xls Management’s goal is to be able to offer service that is not perceived as inferior. This goal translates into mean ratings of at least 3 on the 5-point scale in the national market across all three service dimensions.
Based on this sample, average ratings in all major metropolitan areas are _________ to _________ for coverage,
_________ to _________ for absence of dropped calls, _________ to _________ for static, with 95% confidence.
Management can conclude that they have achieved their goal along:
____ coverage _____dropped calls _____ static
Value of a Nationals Uniform
The Nationals General Manager is concerned that his club may not be paying competitive salaries. He has asked you to compare Nationals’ salaries with salaries of players for the closest team in the National League East, the Phillys. He suspects that the Phillys may win more games because they are attracting better players with higher salary offers. Data are in Lab Practice 3 Nationals.xls.
This is a _____tail t test.
p value from one tail t test of difference in team salary means: ______________
Extra Value of a Phillys Uniform. If you conclude that the Phillys do earn higher salaries, estimate the average difference at a 95% level of confidence.
The General Manager can conclude that, relative to the Phillys, the Nationals are paid ___
Less ___the same.
81
On average, players for the Phillys earn _______ to ________ more than players for the Nationals.
The pooled standard error of the difference in mean salaries is: ____________
Illustrate the two teams’ salaries with a column chart.
Confidence in Chinese Imports
Following the recall of a number of products imported from China, the Associated Press- Ipsos Poll asked 1,005 randomly selected adults about the perceived safety of products imported from China. Poll results are below:
.
“When it comes to the products that you buy that are made in China, how confident are you that those products are safe . . . ?”
.
Confident
Not
Confident Unsure
% % %
42 57 1
Use this data to construct an approximate, conservative 95% confidence interval for the proportion Not Confident that Chinese imports are safe.
________ to ________ percent are not confident that products made in China are safe.
Illustrate your result with a pie chart which includes the margin of error in a text box.
Add a “bottom line” title.
Lab Practice 3 Inference