Answer:
The 99% confidence interval estimate of the percentage of girls born is (86.04%, 93.96%). Considering the actual percentage of girls born is close to 50%, the percentage increased considerably with this method, which means that it appears effective.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of
.
In the study 380 babies were born, and 342 of them were girls.
This means that
99% confidence level
So
, z is the value of Z that has a p-value of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:

As percentages:
0.8604*100% = 86.04%.
0.9396*100% = 93.96%.
The 99% confidence interval estimate of the percentage of girls born is (86.04%, 93.96%). Considering the actual percentage of girls born is close to 50%, the percentage increased considerably with this method, which means that it appears effective.
15 7/11 I think im not sure
Answer:
(y+7x^3) (y-7x^3)
Step-by-step explanation:
Answer:
Step-by-step explanation:
a). Mean of the given data set = 
= 28
b). x

32 32-28 = 4 16
28 28 - 28 = 0 0
18 18 - 28 = -10 100
40 40 - 28 = 12 144
22 22 - 28 = -6 36
= 296
c). Standard deviation = 
= 
= 7.69
d). Mean of the new set of weights = 
= 34
Since mean of the data set is more close to each data, standard deviation will be less than the deviation given in part (c).
Huh english is this spanish !