Answer:
the graph corresponds to function "D" 
Step-by-step explanation:
Since the graph shown corresponds to an exponential "decay" (the function decreases as we move from left to right), the base of the exponent has to be a number smaller than 1 (one). So we examine the only two options that give such (options C and D which have fractions as the base - 1/3 and 1/5 respectively)
From there, we analyze which of the two functions satisfies the crossing of the y-axis at (0,3) which is clearly shown in the graph:
We study both:
function C at x = 0 gives:

while function D at x = 0 gives:

Therefore, the graph corresponds to function "D"
4.2% of 50 is 2.1
So 2.1 is your answer
Answer:
90% confidence interval for the mean weight loss for the population represented by this sample assuming that the differences are coming from a normally distributed population is [1.989 ,13.5105]
Step-by-step explanation:
The data given is
Mean Std Dev
Before 177.25 29.325
After 169.50 22.431
Difference 7.75 8.598
Hence d`= 7.75 and sd= 8.598
The 90% confidence interval for the difference in means for the paired observation is given by
d` ± t∝/2(n-1) *sd/√n
Here t∝/2(n-1)=1.895 where n-1= 8-1= 7 d.f
and ∝/2= 0.1/2=0.05
Putting the values
d` ± t∝/2(n-1) *sd/√n
7.75 ±1.895 * 8.598 /√8
7.75 ± 5.7605
1.989 ,13.5105
90% confidence interval for the mean weight loss for the population represented by this sample assuming that the differences are coming from a normally distributed population is [1.989 ,13.5105]
This is a systems of equation problem.
First, set up the equation.
814=w+d w=d-36
Second, insert w= in for w in the equation.
814=d-36+d
Third, combine like terms.
814=2d-36
Fourth, solve the equation by adding 36 and dividing by 2 to both sides.
814=2d-36
+36 +36
___________
850=2d
----- ----
2 2
__________
425=d
So the dryer (d) costs $425.