Answer:
And rounded up we have that n=99
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by 
and 
. And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that 
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We assume the value for 
since we don't have previous info. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=99
Answer:
Calculus
Step-by-step explanation:
Calculus: z = (94-70)/12 = 2
Bio: z = (74.5-77)/10 = -0.25
History: z = (45-53)/16 = -0.5
Physics: (70.5-60)/14 = 0.75
Since 3/5 of the students wore blue shirts and 1/4 of the students wore white shirts, you need to find the Total of 3/5 and 1/4.
First, step find a common denominator for both fractions
EXAMPLE: 3/5+1/4=Total 3/5 becomes 12/20 and 1/4 becomes 5/20.
Second, notice that both fractions now have the same denominator, now you can find the sum of both fractions which is 17/20
Finally, you need to check if the fraction can be SIMPLIFIED if not then the fraction is already im simplest form.
THE ANSWER: 17/20 of students wore either a blue or white shirt on Friday
Answer:
Ivan got £90 more than Tanya.
Step-by-step explanation:
Ivan and Tanya share the amount £150 in the ratio of 4 : 1
Amount received by Ivan = 
= 
= £120
Similarly, amount received by Tanya = 
= £30
Difference in their amounts = 120 - 30
= £90
Therefore, Ivan got £90 more than Tanya.
