Answer:
(a) 3, 5 and 6
Step-by-step explanation:
In the experiment, 43 are to be given a gel that contains the tooth-whitening chemicals while the remaining 42 are to be given a placebo. Therefore, a placebo is used.
The 43 that will receive the gel are to be selected randomly.
After the experiment, the whiteness of the two groups will be compared to see the effect of the gel.
Therefore for the experiment to be completely random, 3, 5, and 6 apply.
(b)
For the experiment to be double-blind, the researchers who will evaluate the whiteness and interact with the subjects, and the subjects would not know which subjects received either the whitening gel or the placebo.
Answer:
-1/2
Step-by-step explanation:
y2-y1 = -5-0 =-5
x2-x1 = 8-(-2)=10
-5/10= -1/2
Answer:
-17
Step-by-step explanation:
simple math
we have

we know that
this is the equation of a line, to identify which is the graph we will proceed to determine the points of intersection with the coordinate axes
1) <u>Find the y-intercept</u>
the y-intercept is when the value of x is equal to zero
For 
find the value of y


2) <u>Find the x-intercept </u>
the x-intercept is when the value of y is equal to zero
For 
find the value of x


therefore
the answer is the option B ( see the attached figure)
Answer: 72.78% of the drivers are traveling between 70 and 80 miles per hour based on this distribution.
Step-by-step explanation:
Let X be a random variable that represents the speed of the drivers.
Given: population mean : M = 72 miles ,
Standard deviation: s= 3.2 miles
The probability that the drivers are traveling between 70 and 80 miles per hour based on this distribution:
![P(70\leq X\leq 80)=P(\frac{70-72}{3.2}\leq \frac{X-M}{s}\leq\frac{80-72}{3.2})\\\\= P(-0.625\leq Z\leq 2.5)\ \ \ \ \ [Z=\frac{X-M}{s}]\\\\=P(Z\leq2.5)-P(Z\leq -0.625)\\\\\\ =0.9938-0.2660\ \ \ [\text{Using p-value calculator}]\\\\=0.7278](https://tex.z-dn.net/?f=P%2870%5Cleq%20X%5Cleq%2080%29%3DP%28%5Cfrac%7B70-72%7D%7B3.2%7D%5Cleq%20%5Cfrac%7BX-M%7D%7Bs%7D%5Cleq%5Cfrac%7B80-72%7D%7B3.2%7D%29%5C%5C%5C%5C%3D%20P%28-0.625%5Cleq%20Z%5Cleq%202.5%29%5C%20%5C%20%5C%20%5C%20%5C%20%5BZ%3D%5Cfrac%7BX-M%7D%7Bs%7D%5D%5C%5C%5C%5C%3DP%28Z%5Cleq2.5%29-P%28Z%5Cleq%20-0.625%29%5C%5C%5C%5C%5C%5C%20%3D0.9938-0.2660%5C%20%5C%20%5C%20%5B%5Ctext%7BUsing%20p-value%20calculator%7D%5D%5C%5C%5C%5C%3D0.7278)
Hence, 72.78% of the drivers are traveling between 70 and 80 miles per hour based on this distribution.