Question

We discovered that 650 GSS respondents in 2006 watched television for an average of 2.98 hrs/day, with a standard deviation of 2.4 hours. Answer the following questions, assuming the distribution of the number of television hours is normal. What is the Z score for a person who watches more than 8 hrs/day. What proportion of people watch 5 hrs/day or more television? How many does this correspond to in the sample? What number of television hours per day corresponds to a Z +1. What is the percentage of people who watch between 1 and 6 hours of television per day? Please round to a whole number

Answer 1

Answer:

a) 2.09167

b) 0.2

c) 130 correspondents

d) 5.38 hours per day

e) 69%

Step-by-step explanation:

The formula for calculating a z-score is is z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation.

Mean = 2.98hrs/day, Standard Deviation = 2.4

a) What is the Z score for a person who watches more than 8 hrs/day.

z = 8 - 2.98/2.4

= 2.09167

b) What proportion of people watch 5 hrs/day or more television?

z = 5 - 2.98/2.4

z = 0.84167

Determining the Probabilityvalue from Z-Table:

P(x<5) = 0.80001

The proportion of people watch 5 hrs/day or more television

P(x>5) = 1 - P(x<5) = 0.19999

Approximately = 0.2

c) How many does this correspond to in the sample?

From the question above, we are told that: there are 650 GSS respondents in 2006 watched television

Hence the proportion that corresponds to Question b is

0.2 × 650

= 130 correspondents

Therefore, 130 correspondents watch 5 hrs a day or more television

d) What number of television hours per day corresponds to a Z = +1.

z score formula is given as:

z = (x-μ)/σ

Z = +1

x = unknown

Mean = 2.98

Standard deviation = 2.4

Hence:

1 = x - 2.98/2.4

Cross Multiply

1 × 2.4 = x - 2.98

2.4 = x - 2.98

2.4 + 2.98 + x

= 5.38 hours per day.

e)What is the percentage of people who watch between 1 and 6 hours of television per day?

For x = 1

z = 1 - 2.98/2.4

z = -0.825

Probability value from Z-Table:

P(x= 1) = 0.20469

For x = 6

z = 6 - 2.98/2.4

z = 1.25833

Probability value from Z-Table:

P(x = 6) = 0.89586

The percentage of people who watch between 1 and 6 hours of television per day is calculated as:

P(x = 6) - P(x = 1)

0.89586 - 0.20469

= 0.69117

Converting to percentage,

0.69117 × 100%

= 69.117%

To the nearest whole number = 69%

Therefore, 69% of the people who watch between 1 and 6 hours of television per day