Answer:

And replacing we got:

And then the estimator for the standard error is given by:

Step-by-step explanation:
For this case we have the following dataset given:
20.05, 20.56, 20.72, and 20.43
We can assume that the distribution for the sample mean is given by:

And the standard error for this case would be:

And we can estimate the deviation with the sample deviation:

And replacing we got:

And then the estimator for the standard error is given by:

Answer:
a) P=0.2503
b) P=0.2759
c) P=0.3874
d) P=0.2051
Step-by-step explanation:
We have this information:
25% of American households have only dogs (one or more dogs)
15% of American households have only cats (one or more cats)
10% of American households have dogs and cats (one or more of each)
50% of American households do not have any dogs or cats.
The sample is n=10
a) Probability that exactly 3 have only dogs (p=0.25)

b) Probability that exactly 2 has only cats (p=0.15)

c) Probability that exactly 1 has cats and dogs (p=0.1)

d) Probability that exactly 4 has neither cats or dogs (p=0.5)

if he works at the theater he can make $288 in 32 hours, if he works at his aunts he can make $224 in 32 hours. he should work at the theater to meet his goal.
I really hope this helps