In: Statistics and Probability
what follows use any of the following tests/procedures: Regression, multiple regression, confidence intervals, one sided T-test or two sided T-test. All the procedures should be done with 5% P-value or 95% confidence interval.Some answers are approximated, choose the most appropriate answer. Open Brains data. SETUP: Some people believe that the first born children are more intelligent. Given the data your job is to confirm or disprove this assertion.
I. What test/procedure did you perform? (6.66 points)
II. Statistical interpretation? (6.66 points)
III. Conclusion? (6.66 points)
CCMIDSA: Corpus Collasum Surface Area (cm2) FIQ: Full-Scale IQ HC: Head Circumference (cm) ORDER: Birth Order PAIR: Pair ID (Genotype) SEX: Sex (1=Male 2=Female) TOTSA: Total Surface Area (cm2) TOTVOL: Total Brain Volume (cm3) WEIGHT: Body Weight (kg) 8.42 96 57.2 1 6 1 1806.31 1079 61.236 7.44 88 57.2 1 7 1 2018.92 1104 79.38 6.84 85 57.2 1 8 1 2154.67 1439 99.792 6.48 97 57.2 1 9 1 1767.56 1029 81.648 6.43 124 58.5 1 10 1 1971.63 1160 72.576 7.62 101 57.2 2 6 1 1689.6 1173 61.236 6.03 93 57.2 2 7 1 2136.37 1067 83.916 6.59 94 55.8 2 8 1 1966.81 1347 97.524 7.52 114 56.5 2 9 1 1827.92 1100 88.452 7.67 113 59.2 2 10 1 1773.83 1204 79.38 6.08 96 54.7 1 1 2 1913.88 1005 57.607 5.73 87 53 1 2 2 1902.36 1035 64.184 6.22 101 57.8 1 3 2 2264.25 1281 63.958 5.8 103 56.6 1 4 2 1866.99 1051 133.358 7.99 127 53.1 1 5 2 1743.04 1034 62.143 7.99 89 54.2 2 1 2 1684.89 963 58.968 8.76 87 52.9 2 2 2 1860.24 1027 58.514 6.32 103 56.9 2 3 2 2216.4 1272 61.69 6.32 96 55.3 2 4 2 1850.64 1079 107.503 7.6 126 54.8 2 5 2 1709.3 1070 83.009
We need to check the claim that the first born children are more
intelligent.
Here, the independent variable is the Birth Order and the dependent
variable is the FIQ: Full-scale IQ.
We have two independent groups here, those who were born first
and second i.e Birth order = 1 and 2
Hence, we will use the independent samples t-test.
mu1 is the mean IQ of children born first and mu2 for born second
Ho: mu1 <= mu2
Ha: mu1 > mu2
We will use the one sided t-test (right-tailed)
I. Correct option: A)
II. We have the following sampling data:
FIQ (Order = 1) | FIQ (Order = 2) |
96 | 101 |
88 | 93 |
85 | 94 |
97 | 114 |
124 | 113 |
96 | 89 |
87 | 87 |
101 | 103 |
103 | 96 |
127 | 126 |
Let's conduct the t-test in Excel or any other software of your choice.
In excel, go to data -> data analysis -> independent sample t-test assuming equal variances -> Select the data -> Click OK
The results are:
t-Test: Two-Sample Assuming Equal Variances | ||
FIQ (Order = 1) | FIQ (Order = 2) | |
Mean | 100.4 | 101.6 |
Variance | 210.2666667 | 157.3777778 |
Observations | 10 | 10 |
Pooled Variance | 183.8222222 | |
Hypothesized Mean Difference | 0 | |
df | 18 | |
t Stat | -0.197909774 | |
P(T<=t) one-tail | 0.422666778 | |
t Critical one-tail | 1.734063607 | |
P(T<=t) two-tail | 0.845333556 | |
t Critical two-tail | 2.10092204 |
p-value (one-tailed) = 0.423
We fail to reject the null hypothesis as the p-value > 0.05, the test is deemed to be inconclusive.
Correct option: c. Since P-value is too large the test is inconclusive.
III. Conclusion: B. No, we cannot confirm the assertion.