Answer:
There were 20 questions on the quiz
Step-by-step explanation:
In this question, we are concerned with knowing the number of questions on a quiz, given that Deana had a certain percentage after scoring an amount of marks.
We proceed as follows;
Let the number of questions on the quiz be X.
Now, she got 85% by making 3 incorrect choices. This means the percentage of questions she got incorrectly would be 100-85 = 15%
what we are saying is that it is just 15% of her questions that were wrong.
This mathematically;
15% of x = 3
15/100 * x = 3
15x = 3 * 100
15x = 300
x = 300/15
x = 20
Given:
Sample mean = 65.4
Standard deviation = 1.2
Sample size = 45
Confidence level = 99%
To find:
The confidence interval.
Solution:
The formula for confidence interval is
where, 
is sample mean, z* is confidence value, s is standard deviation and n is sample size.
Confidence value or z-value at 99% = 2.58
Putting the given in the above formula, we get
Therefore, the correct option is D.
Let Ch and C denote the events of a student receiving an A in <u>ch</u>emistry or <u>c</u>alculus, respectively. We're given that
P(Ch) = 88/520
P(C) = 76/520
P(Ch and C) = 31/520
and we want to find P(Ch or C).
Using the inclusion/exclusion principle, we have
P(Ch or C) = P(Ch) + P(C) - P(Ch and C)
P(Ch or C) = 88/520 + 76/520 - 31/520
P(Ch or C) = 133/520
Ninety-five hundreths is equivalent to
.
The numerator and denominator have a basic factor of 5, so we can divide the numerator and denominator by 5.
