Estimation: When you have selected the t-statistic and the theory-based
overlay, you can also use this applet for estimating the parameter of interest.
(You can also go directly to the Theory-Based Inference applet which will also
allow you to change the confidence level.) Check the box next to 95% CI(s) for
difference in means.
a. Identify, in words related to
the context of this study, the relevant parameter to be estimated here.
Â b. Report the 95% confidence
interval for this parameter.
c. Does the 95% confidence
interval calculated from the GSS sample data contain the value 0? What does
that imply? (Hint: Recall that a confidence interval is an interval of
plausible values for the parameter of interest, and the interval is calculated
using the sample statistics.)
d. Does the 95% confidence
interval agree with your conclusion in #16? How are you deciding?
Â e. Fill in the blanks of the
sentence below to complete the interpretation of the 95% confidence interval:
We are _______% confident that the mean number of close friends men have is
___________ than the mean number of close friends that women have, by between
________ and _______ friends. f. How would the width of the interval change if
you increased the confidence level to 99%? Why?
Â g. How would the width of the
interval change if you increased the sample size? Why?
Â h. How would the width of the
interval change if the variability of the number of close friends increased for
both males and females? Why?