Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-
, where
is the sample mean and ME is the margin of error .
Given : The sample mean : 
Margin of error : 
Then , the range of values (confidence interval) likely to contain the true value of the population parameter will be :-

Hence, the range of values likely to contain the true value of the population parameter = 
$123 = ($3b + $8.50c)
b + c = 30
b = 24 birds ($72)
c = 6 cats ($51)
51+72=123
There were 24 birds at the shelter on Tuesday.
Answer:

And on this case if we see the significance level given
we see that
so we fail to reject the null hypothesis that the observed outcomes agree with the expected frequencies at 10% of significance.
Step-by-step explanation:
A chi-square goodness of fit test determines if a sample data obtained fit to a specified population.
represent the p value for the test
O= obserbed values
E= expected values
The system of hypothesis for this case are:
Null hypothesis: ![O_i = E_i[/tex[Alternative hypothesis: [tex]O_i \neq E_i](https://tex.z-dn.net/?f=O_i%20%3D%20E_i%5B%2Ftex%5B%3C%2Fp%3E%3Cp%3EAlternative%20hypothesis%3A%20%5Btex%5DO_i%20%5Cneq%20E_i%20)
The statistic to check the hypothesis is given by:

On this case after calculate the statistic they got: 
And in order to calculate the p value we need to find first the degrees of freedom given by:
, where k represent the number of levels (on this cas we have 10 categories)
And in order to calculate the p value we need to calculate the following probability:

And on this case if we see the significance level given
we see that
so we fail to reject the null hypothesis that the observed outcomes agree with the expected frequencies at 10% of significance.
Answer:
1. 1/7
2. 3/10
Step-by-step explanation:
4/28 can be divided by 4
24/80 can be divided by 8