Answer:
Option a is right
a) Since the subjects were not randomly selected for the study, we cannot conclude that a reduction in cavities can be attributed to the fluoride treatment.
Step-by-step explanation:
Given that in an experiment to measure the effect of fluoride "varnish" on the incidence of tooth cavities, 34 10-year-old-girls whose parents volunteered them for the study were raOne group was given fluoride varnish annually for 4 years along with a standard dental hygiene regimen;
the other group only followed the standard dental hygiene regimen.
The mean number of cavities in the two groups was compared at the end of the treatments. ndomly assigned to two groups.
Because they have selected 34 volunteers, the sample is not selected at random. This is biased one. Also sample size is very small compared to 10 year old girls in the world.
a) Since the subjects were not randomly selected for the study, we cannot conclude that a reduction in cavities can be attributed to the fluoride treatment.
is the right answer
Answer:
3-they are cubes of consecutive natural numbers
1 cube is 1
2 cube is 8
3 cube is 27
and so on...
let me know if you're asking fourth one or third one
Answer:
x=4
Step-by-step explanation:
y = x + 4/x
replace x with -x. Do you get back the original equation after simplifying. if you do, the function is even.
replace y with -y AND x with -x. Do you get back the original equation after simplifying. If you do, the function is odd.
A function can be either even or odd but not both. Or it can be neither one.
Let's first replace x with -x
y = -x + 4/-x = -x - 4/x = -(x + 4/x)
we see that this function is not the same because the original function has been multiplied by -1
. Let's replace y with -y and x with -x
-y = -x + 4/-x
-y = -x - 4/x
-y = -(x + 4/x)
y = x + 4/x
This is the original equation so the function is odd.
Answer:
7
Step-by-step explanation:
I assume that 3,14 is 3.14
=3.14 x (200-175)2 - 150
=3.14 x (25)2 - 150
=3.14 x 50 - 150
=157-150
=7
