Submitted by: Submitted by helenaoh
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Pages: 3
Category: Other Topics
Date Submitted: 06/10/2013 09:04 AM
Answers
1-(b)
> inference(data = bv1960$blackreg, group = bv1960$dv, est = "mean", type = "ht", null = 0 ,alternative = "greater", order = c("bstate","dstate"), method = "theoretical")
Response variable: numerical, Explanatory variable: categorical
Difference between two means
Summary statistics:
n_bstate = 423, mean_bstate = 34.7187, sd_bstate = 23.4563
n_dstate = 660, mean_dstate = 25.703, sd_dstate = 24.225
Observed difference between means (bstate-dstate) = 9.0156
H0: mu_bstate - mu_dstate = 0
HA: mu_bstate - mu_dstate > 0
Standard error = 1.48
Test statistic: Z = 6.092
p-value = 0
2-(1)
> lm2=lm(blackreg~dv, data=bv1960)
> summary(lm2)
Call:
lm(formula = blackreg ~ dv, data = bv1960)
Residuals:
Min 1Q Median 3Q Max
-34.719 -17.719 -4.719 11.297 73.297
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 34.719 1.163 29.84 <2e-16 ***
dvdstate -9.016 1.490 -6.05 2e-09 ***
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Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
Residual standard error: 23.93 on 1081 degrees of freedom
(53 observations deleted due to missingness)
Multiple R-squared: 0.03275, Adjusted R-squared: 0.03185
F-statistic: 36.6 on 1 and 1081 DF, p-value: 1.999e-09
3-(a)
1.
> lm1=lm(blackreg~strigh48, data=bv1960)
> summary(lm1)
Call:
lm(formula = blackreg ~ strigh48, data = bv1960)
Residuals:
Min 1Q Median 3Q Max
-37.393 -13.750 -5.245 9.782 83.926
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 37.3930 0.9313 40.15 <2e-16 ***
strigh48 -0.2937 0.0225 -13.05 <2e-16 ***
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Signif. codes: 0 ‘***’...