Note that the values in a single column add up to the value in the Total row.
B
Compare the number of rainy Fridays, Saturdays, and Sundays, using the table from Part A.
A
Weather
Day
Rain
No Rain
Total
Friday
6
14
20
Saturday
5
15
20
Sunday
7
13
20
Total
18
42
60
B
Saturday, see solution.
Practice makes perfect
We want to construct a two-way frequency table based on the information about the weather Demi and Margaret recorded. Let's first convert the notes from Margaret about the weather in NYC to a table that will follow the final format.
Weather
Day
Rain
No Rain
Total
Friday
4
6
Saturday
5
5
Sunday
6
4
Total
Now, we will add the information that Demi recorded about the weather in LA.
Weather
Day
Rain
No Rain
Total
Friday
4 + 2 = 6
6 + 8 = 14
Saturday
5 + 0 = 5
5 + 10 = 15
Sunday
6 + 1 = 7
4 + 9 = 13
Total
Note that the values in a single row add up to the value in the Total column.
Friday Total: &6 + 14 = 20
Saturday Total:& 5 + 15 = 20
Sunday Total: &7 + 13 = 20
We can add the obtained numbers to the table.
Weather
Day
Rain
No Rain
Total
Friday
6
14
20
Saturday
5
15
20
Sunday
7
13
20
Total
Once again, we will use the fact that the sum of the values in a single column is the value in Total row. Therefore, we can calculate the total number of days with and without rain.
Rain Total: &6 + 5 +7 = 18
No Rain Total:& 14 + 15 +13 = 42
We will write the obtained numbers in the last row of our table.
Weather
Day
Rain
No Rain
Total
Friday
6
14
20
Saturday
5
15
20
Sunday
7
13
20
Total
18
42
t
Finally, let t be the total number of days during which the girls recorded the weather. We can choose either the Total row or Total column to calculate the value of t. Remember that they must be the same!
Row Total:& t= 18+ 42= 60
Column Total:& t= 20 + 20+ 20= 60
Since we got the same answer in both cases, we can be sure that we made no mistakes. With this in mind, we can finish our table!
Weather
Day
Rain
No Rain
Total
Friday
6
14
20
Saturday
5
15
20
Sunday
7
13
20
Total
18
42
60
We want to use the table obtained in Part A to answer the following question.
Which day saw the least rain?
According to the table, we can list the numbers of rainy Fridays, Saturdays, and Sundays.
ccc
Friday & Saturday & Sunday
6 & 5 & 7
This means that the day that saw the least rain is Saturday.
