Question Video: Forming a Frequency Table for a Data Set Then Reading the Data | Nagwa Question Video: Forming a Frequency Table for a Data Set Then Reading the Data | Nagwa

# Question Video: Forming a Frequency Table for a Data Set Then Reading the Data Mathematics

The table of data shows the heights in centimeters of teachers at a school. Using a frequency table, find the number of teachers whose heights are greater than or equal to 175 cm.

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### Video Transcript

The table of data shows the heights in centimeters of teachers at a school. Using a frequency table, find the number of teachers whose heights are greater than or equal to 175 centimeters.

Our first step in this question is to create a grouped frequency table from the data in the table. The lowest number in the table is 155, which corresponds to a height of 155 centimeters. And the highest number in the table is 195, which corresponds to a height of 195 centimeters.

The first row of the frequency table will be the heights of the teachers, and the second row will be the frequency. We will split the data into five groups: 155 to 164 centimeters, 165 to 174 centimeters, 175 to 184 centimeters, 185 to 194 centimeters, and 195 to 204 centimeters, noting that it is common practice for all groups to have the same width.

There are 12 teachers that had a height between 155 and 164 centimeters. So the first frequency is 12. Next, we see that there are 14 teachers with a height between 165 and 174 centimeters. Nine of the teachers in the table are in the third group: 175 to 184 centimeters. There are 10 teachers who had a height between 185 and 194 centimeters. Finally, there are three teachers who are 195 centimeters tall. And as already mentioned, this is the largest value in the table. So the final frequency is three.

At this stage, it is worth checking we have counted every item of data from the table. 12 plus 14 plus nine plus 10 plus three equals 48, which means we have counted each value from the table. The question asks us to calculate how many teachers have a height greater than or equal to 175 centimeters. As such, we need one of the lower class boundaries to be 175 centimeters. And this corresponds to the last three columns in the grouped frequency table. We need to add the frequencies of nine, 10, and three. This is equal to 22.

We can therefore conclude that 22 teachers have a height greater than or equal to 175 centimeters.