Question

Here are summary statistics for randomly selected weights of newborn​ girls:

nequals=211211​,

x overbarxequals=27.127.1

​hg,

sequals=6.76.7

hg. Construct a confidence interval estimate of the mean. Use a

9898​%

confidence level. Are these results very different from the confidence interval

25.725.7

hgless than<muμless than<29.329.3

hg with only

1414

sample​ values,

x overbarxequals=27.527.5

​hg, and

sequals=2.52.5

​hg?What is the confidence interval for the population mean

muμ​?

nothing

hgless than<muμless than<nothing

hg ​(Round to one decimal place as​ needed.)

Enter your answ

Answer 1

Solution :

degrees of freedom = n - 1 = 211 - 1 = 210

t/2,df = t0.01,210 = 2.344

Margin of error = E = t/2,df * (s /n)

= 2.344 * ( 6.7 / 211)

Margin of error = E = 1.1

The 98% confidence interval estimate of the population mean is,

- E < < + E

27.1 - 1.1 < < 27.1 + 1.1

26.0 hg < < 28.2 hg

Yes, because the confidence interval limits are not similar