Answer:
2/3 per brother
Step-by-step explanation:
2/3 plus 2/3 plus 2/3 is 6
Answer:
Step-by-step explanation:
Sample proportion p is the proportion of favourable numbers to total number in the sample
By central limit theorem and also approximation of binomial to normal , we have sample proportion for large number of samples will be normal
with mean = sample proportion
and std deviation = 
Thus we find standard deviation of proportion sample is inversely proportional to the square of the sample size n.
It follows automatically that as sample size increases std deviation decreases.
Here from 80 sample size was made to 200
So std deviation would decrease automatically
Answer:
A. principal interviewed the 25 students who scored highest on a reading test.
D. For a report on the exercise habits of adults, Sergio talked to 30 adults at a local fitness center.
E. Josh asked the first 25 people he met at the dog park if they preferred dogs or cats.
Step-by-step explanation:
Biased means if the selection of every unit does not have an equal chance of being selected in a sample.
The sample is said to be good if choosing the unit is unbiased. The sample is said to be unbiased if the selection of each unit is independent.
Option A is an example of data selected in a biased way because principal chose only those student who scored the highest marks on reading test.
Options B and C are unbiased as here a selection of each number and name of the student has an equal chance of being selected.
Option D is biased because Sergio talked adults at a local fitness center where people go for maintaining their health. So, there is a chance of the selection of fitted adults more than unfitted adults.
Option E is biased because Josh met people at the dog park where dog lovers are more than a cat lover.
