Question

micah surveys a random sample of 20 band members from his school to find out how many minutes they practice their instruments each day. the results are shown in the dot plot. based on the data from the sample, about what percent of all band members practice their instruments less than 20 minutes per day? 1% 5% 15% 20% daily instrument practice 10 20 30 40 50 60 time (min)

Explanation:

Step1: Count the number of band members who practice less than 20 minutes

From the dot - plot, the number of band members who practice less than 20 minutes is \(1 + 3=4\)

Step2: Calculate the percentage

The formula for percentage is \(\text{Percentage}=\frac{\text{Number of favorable cases}}{\text{Total number of cases}}\times100\%\)
Here, the total number of cases \(n = 20\), and the number of favorable cases \(m = 4\)
\(\text{Percentage}=\frac{4}{20}\times100\%=\frac{4\times100\%}{20}=20\%\)

Answer:

\(20\%\)