In: Statistics and Probability
district | percentage working class | unemployment rate | voter turnout |
1 | 50 | 10 | 56 |
2 | 45 | 12 | 55 |
3 | 56 | 8 | 52 |
4 | 78 | 15 | 60 |
5 | 13 | 5 | 89 |
6 | 85 | 20 | 25 |
7 | 62 | 18 | 64 |
8 | 33 | 9 | 88 |
9 | 25 | 0 | 42 |
10 | 49 | 9 | 36 |
The following data was collected for a random sample of 10 electoral districts during the last federal election. The first variable reports the percentage of individuals in each district who belong to the working class; the second variable reports the percentage of individuals who are unemployed; and the third variable reports the percentage of eligible individuals (i.e., citizens at least 18 years old) who voted in the last federal election.
Find the mean and standard deviation of each of the three variables. Round to 2 decimal places.
A) (i) Percentage working-class B) (ii) Unemployment rate C) (iii) Voter turnout
How would you describe the distribution of the variable percentage working-class?
(a) Approximately bell-shaped or symmetric or Normal (b) Left (or negatively) skewed (c) Right (or positively) skewed) (d) Too little information to tell
Calculate the correlation between each pair of variables. Round to 2 decimal places.
a) (i) Percentage working-class & unemployment rate b) (ii) Percentage working-class & voter turnout c) (iii) Unemployment rate & voter turnout
Calculate the appropriate test statistic for each correlation. Round to 2 decimal places.
a) (i) Percentage working-class & unemployment rate b) (ii) Percentage working-class & voter turnout c (iii) Unemployment rate & voter turnout
Find the critical value of t (α = .05) for each correlation.
a) (i) Percentage working-class & unemployment rate b) (ii) Percentage working-class & voter turnout c) (iii) Unemployment rate & voter turnout
setting your level of significance at α = .05, for which pairs of variables did you find a statistically significant relationship? Choose all that apply.
(a) Percentage working-class & unemployment rate (b)
Percentage working-class & voter turnout (c) Unemployment rate
& voter turnout
(d) None of the pairs are significantly related to one another.
for percentage working class
X | (X - X̄)² | |
total sum | 496 | 4496.40 |
n | 10 | 10 |
mean = ΣX/n = 496.000
/ 10 = 49.60
sample std dev = √ [ Σ(X - X̄)²/(n-1)] =
√ (4496.4/9) =
22.35
...................
for unemployment rate
X | (X - X̄)² | |
total sum | 106 | 320.40 |
n | 10 | 10 |
mean = ΣX/n = 106.000
/ 10 = 10.60
sample std dev = √ [ Σ(X - X̄)²/(n-1)] =
√ (320.4/9) =
5.97
....................
for voter turnout
X | (X - X̄)² | |
total sum | 567 | 3762.10 |
n | 10 | 10 |
mean = ΣX/n = 567.000
/ 10 = 56.70
sample std dev = √ [ Σ(X - X̄)²/(n-1)] =
√ (3762.1/9) =
20.45
.......................
for percentage working class: almost bell shaped
for unemployment rate: skewed to left
for voter turnout : skewed to right
..........................
for percentage working class and unemployment rate
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 496 | 106 | 4496.4 | 320.4 | 1019.40 |
mean | 49.60 | 10.60 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy)
= 0.8493
correlation hypothesis test
Ho: ρ = 0
tail= 2
Ha: ρ ╪ 0
n= 10
alpha,α = 0.05
correlation , r= 0.8493
t-test statistic = r*√(n-2)/√(1-r²) =
4.551
critical t-value =
2.3060
DF=n-2 = 8
Decison: test stat >critical , So, Reject
Ho
........................
for percentage working class and voter turnout
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 496 | 567 | 4496.4 | 3762.1 | -2288.20 |
mean | 49.60 | 56.70 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy)
= -0.5563
correlation hypothesis test
Ho: ρ = 0
tail= 2
Ha: ρ ╪ 0
n= 10
alpha,α = 0.05
correlation , r= -0.5563
t-test statistic = r*√(n-2)/√(1-r²) =
-1.894
critical t-value = 2.3060
DF=n-2 = 8
Decison: critical value > test stat, So, Do not
reject Ho
..................
for unemployment rate and voter turnout
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 106 | 567 | 320.4 | 3762.1 | -261.20 |
mean | 10.60 | 56.70 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy)
= -0.2379
correlation hypothesis test
Ho: ρ = 0
tail= 2
Ha: ρ ╪ 0
n= 10
alpha,α = 0.05
correlation , r= -0.2379
t-test statistic = r*√(n-2)/√(1-r²) =
-0.693
critical t-value = 2.3060
DF=n-2 = 8
Decison: test stat < critical value, So, Do not
reject Ho
.....................
this pair has statistically significant relationship
(a) Percentage working-class & unemployment
rate
..............................
Please revert back in case of any doubt.
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