In: Statistics and Probability
For each of the following questions, report 1) the appropriate statistical test or estimation procedure to use, 2) the null and alternate hypotheses, 3) the test statistic, 4) the P value, 5) whether you accept or reject the null, then 6) a sentence or two about what the results mean.
Also answer this subpart: What is the relationship between age and height of children? Display data using one graph.
child_age |
child_ht |
5 |
130 |
7 |
135 |
9 |
139 |
8 |
138 |
7 |
125 |
8 |
129 |
5 |
133 |
4 |
128 |
4 |
120 |
10 |
140 |
10 |
144 |
12 |
150 |
11 |
134 |
5 |
132 |
8 |
131 |
7 |
128 |
7 |
139 |
9 |
136 |
13 |
161 |
13 |
163 |
14 |
145 |
12 |
141 |
11 |
154 |
11 |
159 |
5 |
132 |
6 |
138 |
7 |
143 |
6 |
134 |
8 |
140 |
9 |
148 |
7 |
140 |
7 |
133 |
9 |
134 |
10 |
151 |
10 |
157 |
12 |
145 |
13 |
161 |
12 |
154 |
13 |
159 |
12 |
132 |
6 |
134 |
7 |
138 |
8 |
145 |
7 |
134 |
5 |
123 |
5 |
136 |
5 |
133 |
14 |
167 |
12 |
158 |
12 |
149 |
8 |
143 |
9 |
145 |
7 |
147 |
6 |
142 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 467 | 7629 | 430.3148148 | 6426.8 | 1283.28 |
mean | 8.65 | 141.28 | SSxx | SSyy | SSxy |
sample size , n = 54
here, x̅ = Σx / n= 8.65 ,
ȳ = Σy/n = 141.28
SSxx = Σ(x-x̅)² = 430.3148
SSxy= Σ(x-x̅)(y-ȳ) = 1283.3
estimated slope , ß1 = SSxy/SSxx =
1283.3 / 430.315 =
2.9822
intercept, ß0 = y̅-ß1* x̄ =
115.4874
so, regression line is Ŷ =
115.4874 + 2.9822 *x
SSE= (SSxx * SSyy - SS²xy)/SSxx =
2599.863
std error ,Se = √(SSE/(n-2)) =
7.071
correlation coefficient , r = Sxy/√(Sx.Sy)
= 0.7717
2)
slope hypothesis test
tail= 2
Ho: ß1= 0
H1: ß1╪ 0
3)
n= 54
alpha = 0.05
estimated std error of slope =Se(ß1) = Se/√Sxx =
7.071 /√ 430.31 =
0.3409
t stat = estimated slope/std error =ß1 /Se(ß1) =
2.9822 / 0.3409 =
8.7489
4)
t-critical value= 2.007 [excel function:
=T.INV.2T(α,df) ]
Degree of freedom ,df = n-2= 52
p-value = 0.0000
5)
decison : p-value<α , reject Ho
6)
Conclusion: Reject Ho and conclude that slope is
significantly different from zero
7)
Relationship is moderate and positive
THANKS
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