Answer: aA 90% confidence interval for the population proportion of adults in the U.S. who have donated blood in the past two years = (0.163,0.189)
Step-by-step explanation:
Let p = population proportion of adults in the U.S. who have donated blood in the past two years.
Given: A Gallup survey of 2322 adults (at least 18 years old) in the U.S. found that 408 of them have donated blood in the past two years.
Sample size: n= 2322
Sample proportion 
Critical z-value for 90% confidence level : z*=1.645
The confidence interval for population proportion:
A 90% confidence interval for the population proportion of adults in the U.S. who have donated blood in the past two years:
Hence,
Answer:
Explanation:
You can build a two-way relative frequency table to represent the data:
These are the columns and rows:
Car No car Total
Boys
Girl
Total
Fill the table
- <em>30% of the children at the school are boys</em>
Car No car Total
Boys 30%
Girl
Total
- <em>60% of the boys at the school arrive by car</em>
That is 60% of 30% = 0.6 × 30% = 18%
Car No car Total
Boys 18% 30%
Girls
Total
By difference you can fill the cell of Boy and No car: 30% - 18% = 12%
Car No car Total
Boy 18% 12% 30%
Girl
Total
Also, you know that the grand total is 100%
Car No car Total
Boy 18% 12% 30%
Girl
Total 100%
By difference you fill the total of Girls: 100% - 30% = 70%
Car No car Total
Boy 18% 12% 30%
Girl 70%
Total 100%
- <em>80% of the girls at the school arrive by car</em>
That is 80% of 70% = 0.8 × 70% = 56%
Car No car Total
Boy 18% 12% 30%
Girl 56% 70%
Total 100%
Now you can finish filling in the whole table calculating the differences:
Car No car Total
Boy 18% 12% 30%
Girl 56% 14% 70%
Total 74% 26% 100%
Having the table completed you can find any relevant probability.
The probability that a child chosen at random from the school arrives by car is the total of the column Car: 74%.
That is because that column represents the percent of boys and girls that that arrive by car: 18% of the boys, 56% of the girls, and 74% of all the the children.
Pretty sure it would be D
Good luck on your finals!
Answer:
y = -5x +5
Step-by-step explanation:
slope = (15 - -5)/(-2 - 2) = 20/-4 = <u>-5</u>
y int = 5
Step-by-step explanation:
if there is nothing missing, we have
x + 25/-8 = -6
in order to compare or add or subtract fractions, we need to bring them all to the same denominator (bottom part).
remember, integer numbers are fractions too. like here
-6 = -6/1
25/-8 = -25/8
so, how can we bring -6/1 to .../8 ?
by multiplying 1 by 8.
but we cannot multiply only the denominator by 8. otherwise we would suddenly have
-6/8
and is -6/8 = -6/1 ? no, certainly not.
to keep the original value of the fraction we have to do the same multiplication also with the numerator (top part).
so, we actually do
-6/1 × 8/8 = -48/8
with this little trick we have now .../8 to operate with, and our transformed fraction has still the same value
-6/1 = -48/8 indeed.
so, we have
x + -25/8 = -48/8
x - 25/8 = -48/8
x = -48/8 + 25/8 = -23/8
