Question

3. What is the estimated probability that teens spend less than an hour per day texting?

Answer 1

Answer:

0.29

Missing Problem Statement:

The table shows the number of hours, to the nearest half hour per day, that teens spend texting according to a random  

sample of 870 teenagers aged 13–18 in a large urban city.  

Hours          0     0.5    1.0   1.5  2.0   2.5  3.0  3.5  4.0  4.5  5.0

Frequency  170  82    220  153  92   58   40    15  12   18    10

Step by Step Explanation:

First we need to find the estimated probability distribution for teens spending time texting.

For that we need,

Total sample size = 870 teenagers (as given in the problem statement)

Estimated probability distribution (Frequency*) = $\frac{Frequency.Sample.Size.of.that.hour}{Total.Sample.Size}$

Example:

Estimated probability distribution that teens spend 0 hours=$\frac{170}{870} =0.20$

Similarly,

Hours          0     0.5    1.0     1.5    2.0    2.5    3.0    3.5    4.0    4.5    5.0

Frequency*0.2  0.09  0.25  0.18  0.11  0.07  0.05  0.02  0.01  0.02  0.01

We need, estimated probability distribution that teens spend less than an hour per day, so from the above result:

Estimated probability distribution of teens spending 0 hour per day =0.2

Estimated probability distribution of teens spending 0.5 hour per day = 0.09

Estimated probability distribution of teens spending less than an hour per day= 0.2+0.09=0.29

Answer 2

Answer:

$0.29$

Step-by-step explanation:

1) Retrieving the missing data, setting the data orderly in a table.

(Check it below)

2) Add a column for the Relative Frequency. Divide each frequency by the total 870.

3) To estimate probability is always important to work with Relative Frequency. Notice that the question asks the probability of teens that text <1 hour per day, in light yellow.

Adding it up 0.2 +0.09=0.29