Uploaded by Kateryna Ternova

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In this work, we will analyze NBA players’ salary data (for the season 2017 – 2018) and NBA team performance (for the season 2016 – 2017). Our workbook contains two sheets named

“PlayerSalaries17-18” (this sheet contains an information about players’ salaries for the season 2017 –

2018) and “TeamStats16-17 (this sheet contains an information about team performance such as Team

Names, number of games, Number of wins and losses, number of points, etc.).

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According to analysis, the minimum salary in season 2017 – 2018 is $25,000, maximum salary is

$34,682,550, and the mean salary is $5,985,488. The standard deviation is $7,080,216, which means that there is a large difference between salaries (Table 1).

Table 1. Salary Descriptives

Salary 2017-18

Mean

Standard Error

Median

Mode

Standard Deviation

Sample Variance

Kurtosis

Skewness

Range

Minimum

Maximum

Sum

Count

$5,985,488.36

$297,866.92

$2,422,560

$815,615

$7,080,215.82

$50,129,456,038,957

2.160994982

1.694083243

$34,657,550

$25,000

$34,682,550

$3,381,800,925

565

According to the analysis, there are 11 outliers. Thus, there are 11 players, who earn more than

$27,226,136 (more than 3 standard deviations from the mean). Among these 11 players, 2 players are from Toronto Raptors and 2 players are from Boston Celtics. Stephen Curry has the maximum salary of

$34,682,550 (Golden State Warriors).

According to the analysis, we have next data about average salary by the team (see Table 2):

Table 2. Average Salaby by Team

Row Labels

Atlanta Hawks

Boston Celtics

Brooklyn Nets

Charlotte Hornets

Chicago Bulls

Cleveland Cavaliers

Dallas Mavericks

Denver Nuggets

Detroit Pistons

Golden State Warriors

Houston Rockets

Indiana Pacers

Los Angeles Clippers

Los Angeles Lakers

Memphis Grizzlies

Miami Heat

Milwaukee Bucks

Minnesota Timberwolves

New Orleans Pelicans

New York Knicks

Oklahoma City Thunder

Orlando Magic

Philadelphia 76ers

Phoenix Suns

Portland Trailblazers

Sacramento Kings

San Antonio Spurs

Toronto Raptors

Utah Jazz

Washington Wizards

Average of Salary 2017-18 Average 2016-17 Salary

$4,575,886 $5,845,557

$5,957,331

$5,166,784

$6,698,843

$5,251,858

$3,641,612

$6,424,331

$4,146,919

$7,615,551

$4,524,237

$6,460,306

$6,504,632

$6,265,548

$8,405,658

$5,330,733

$4,303,945

$6,078,095

$7,784,448

$6,726,871

$4,660,071

$5,593,486

$5,685,102

$6,603,748

$7,211,870

$6,117,967

$6,881,343

$6,967,893

$5,069,624

$6,626,715

$6,593,855

$5,869,875

$6,457,641

$6,655,795

$6,204,768

$5,737,338

$7,013,350

$5,036,072

$6,523,581

$6,055,882

$7,624,328

$5,457,815

$4,505,440

$4,950,031

$6,557,409

$4,782,720

$6,199,199

$6,721,217

$6,268,493

$7,184,622

$6,681,750

$8,063,418

$3,304,257

$5,056,311

$6,688,123

$5,641,101

$6,037,653

$6,692,496

$5,235,885

$6,142,478

We can compare average salaries for seasons 2016 – 2017 and 2017 – 2018 by using the graph

(see Figure 1):

2

3

$8

$7

$6

$4

$3

$1

$0

Average Salary 2017-18 vs. 2016-17

Average of Salary 2017-18 Average 2016-17 Salary

Team

Figure 1. Average Salary by Team (for two seasons)

As we are able to see from the graph, there is no some tendency in average salaries, i.e. salaries for the season 2017 – 2018 increased for some teams (Golden State Warriors and Miami Heat, for example) and decreased for others (Dallas Mavericks and Atlanta Hawks, for example).

According to the results, 95% of all salaries for the season 2017 – 2018 are in range from

$5,400,424 to $6,570,552.

By using one-sample t-test, we tested the hypothesis that the average salary of the Golden State

Warriors players is greater than $5,593,908:

The level of significance is = 0.05

.

: ≤ $5,593,908

: > $5,593,908

As a result, we’ve received that test statistics is:

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∗ =

$7,784,448 − $5,593,908

$9,901013

√18

= 0.9387.

P-value equal to:

− = 0.1805.

We are able to see that − = 0.1805 > = 0.05

. It means that we fail to reject the null hypothesis. There is insufficient evidence, at the = 0.05

level, to conclude that the average salary of the Golden State Warriors players is greater than $5,593,908.

Descriptive statistics for the variables Age, Average 2016-17 Salary, ORtg, DRtg, Total Points from 2P, Total Points from 3P, and Total Points from FT shows that there are 30 teams: 16 playoff teams and 14 non-playoff teams. The variable Averag2016-17Salary has the highest variation and the DRtg has the lowest variation. The variable DRtg has the lowest (absolute value) skewness and kurtosis coefficients. The variables Age, ORtg, PTS, Total Points from 3P are skewed right or positively skewed as their skewness is positive. The variables Average 2016-17 Salary, DRtg, Total Points from 2P, and Total

Points from FT are skewed left or negatively skewed as their skewness is negative.

The same result for skewness are shown below: variable Age is right skewed (Figure 2), variable

Average2016-17Salary is left skewed (Figure 3), and variable TotalPointsfrom3P is right skewed (Figure

4).

Box-plot for Age

35.00

30.00

25.00

20.00

15.00

10.00

5.00

0.00

Age

Figure 2. Box-Plot for Age

Box-plot for Average Salary 2016 - 17

90

80

70

60

50

40

30

20

10

0

Average Salary

Figure 3. Box-Plot for Average 2016-17 Salary

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Box-plot for Total Points from 3P

50.00

45.00

40.00

35.00

30.00

25.00

20.00

15.00

10.00

5.00

0.00

Total Points from 3P

Figure 4. Box-Plot for Total Points from 3P

According to the results, we are able to see, that playoff teams have higher average salary, average age, ORtg, PTS, Total Points from 3P, and Total Points from FT (Table 3).

Table 3. Playoffs Teams

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Average Values

Playoff Team?

No Yes

Average of Average 2016-17 Salary 5560890.71 6375825.61

Average of Age 25.86 27.23

Average of ORtg 106.86 110.52

Average of DRtg

Average of PTS

110.10

104.11

107.63

106.88

Average of Total Points From 2P

Average of Total Points from 3P

Average of Total Points from FT

59.16

27.62

17.32

58.45

30.11

18.28

According to the results, we have that the average salary for the season 2016-17 is greater for both non-playoff teams and playoff teams in Eastern Conference (see Table 4 and Figure 5).

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Table 4. Salary Comparisons

Conference

Playoff Team?

No Yes

Eastern $ 5,614,990 $ 6,477,763

Western $ 5,506,791 $ 6,296,541

$60

$55

$50

Average Salary by Conference and Playoff Teams

(No/Yes)

Eastern Western Conference

$70

$65

Non-Playoff Playoff

Axis Title

Figure 5. Salary Comparisons

According to the analysis, the correlation coefficient between Win% (percentage of wins) and

Total points from 3P is 0.4468. It means that there is relatively weak positive relationship between these variables. The same conclusion we are able to see on the scatterplot: there is a positive relationship between wins percentage and total points from 3P (Figure 6).

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Win% vs. Total Points from 3P

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

0 10 20 30

Total Points from 3P

40 50

Figure 6. Win% vs. Total Points from 3P

After conducting a regression analysis for the variables Average 2016-17 Salary (independent variable) and Win% (dependent variable), we received that the Win% can be predicted from the average

2016-17 Salary by the equation (Figure 7):

% = 0.22 + 4.68 ∙ 10 ∙ .

The intersection coefficient is = 0.22

, which means that the wins’ percentage will be 0.22 or

22% if the average salary will be $0. The p-value for the intercept is − = 0.1350

. The coefficient = 4.68 ∙ 10 means that each additional dollar in average salary increases the Win% by

4.68 ∙ 10 . The p-value is − = 0.0439

.

The p-value for the regression model is − = 0.0439 < = 0.05

, which means that the model is statistically significant. At the same time, the coefficient of determination is = 0.1372

, which means that the model is quite bad and only 13.72% of variance in dependent variable is predictable from the independent variable. Thus, the model is very weak.

Win% vs. Average Salary 2016-17

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00

$y = 5E-08x + 0.2195

R² = 0.1372

$2,000,000 $4,000,000 $6,000,000 $8,000,000 $10,000,000

Average Salary 2016-17

Figure 7. Win% vs. Average Salary

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