Kendra reads in Modern Dog Magazine that the average age of dogs currently alive is 4.8 years. To determine if this finding applies to the customers in her pet store, Kendra surveys every fifth customer in her store who owns a dog and asks the age of their dog. She collects data for seven weeks and obtains the following averages. Week Average Age (in years)
1 3.7
2 3.8
3 4.2
4 4.1
5 3.9
6 3.9
7 4.0
Select the statement that is true about Kendra's sample.
a) Kendra's samples are both accurate and precise.
b) Kendra's samples are precise but not accurate.
c) Kendra's samples are neither accurate nor precise.
d) Kendra's samples are accurate but not precise.

The true statement about Kendra's sample is:

b) Kendra's samples are precise but not accurate.

Step-by-step explanation:

a) Data and Calculations:

Average age of dogs currently alive = 4.8 years

Average ages of dogs in Kendra's sample

Week   Average Age (in years)

1                    3.7

2                   3.8

3                   4.2

4                   4.1

5                  3.9

6                  3.9

7                  4.0

Total         27.6

Mean = 3.9 (27.6/7)

b) Accuracy refers to how close Kendra's sample mean age of dogs is to the average age value as stated in the Modern Dog Magazine.  While the Magazine stated an average age of 4.8 years, Kendra's sample produced a mean of 3.9 years.  On the other hand, precision refers to how close Kendra's sample measurements are to each other.  With a mean of 3.9 years, the sample measurements are very close to each other.  Therefore, we can conclude that "Kendra's samples are precise but not accurate."

The sum of all positive even values in arr

Explanation:

We have an array named arr holding int values

Inside the method mystery:

Two variables s1 and s2 are initialized as 0

A for loop is created iterating through the arr array. Inside the loop:

num is set to the ith position of the arr (num will hold the each value in arr)

Then, we have an if statement that checks if num is greater than 0 (if it is positive number) and if num mod 2 is equal to 0 (if it is an even number). If these conditions are satisfied, num will be added to the s1 (cumulative sum). If num is less than 0 (if it is a negative number), num will be added to the s2 (cumulative sum).

When the loop is done, the value of s1 and s2 is printed.

As you can see, s1 holds the sum of positive even values in the arr