We are given that a random sample of 250 students at a university finds that these students take a mean of 15.2 credit hours per quarter with a standard deviation of 2.3 credit hours.

Firstly, the pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample credit hours per quarter = 15.2 credit hours

s = sample standard deviation = 2.3 credit hours

n = sample of students = 250

$\mu$ = population mean credit hours per quarter

Here for constructing 95% confidence interval we have used One-sample t test statistics as we know don't about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-1.96 < $t_2_4_9$ < 1.96) = 0.95 {As the critical value of t at 249 degree of

freedom are -1.96 & 1.96 with P = 2.5%}

P(-1.96 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-1.96 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+1.96 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $15.2-1.96 \times {\frac{2.3}{\sqrt{250} } }$ , $15.2+1.96 \times {\frac{2.3}{\sqrt{250} } }$ ]

= [14.915 hours , 15.485 hours]

Therefore, 95% confidence interval for the mean credit hours taken by a student each quarter is [14.915 hours , 15.485 hours].

The interpretation of the above confidence interval is that we are 95% confident that the true mean credit hours taken by a student each quarter will be between 14.915 credit hours and 15.485 credit hours.

8 0

2 years ago

A swimmer can swim 50.2 meters in 1 minute. How far can he swim in half an hour? *

belka [17]

Answer:

1506meters

Step-by-step explanation:

1hour-60minutes

which means half an hour is 30minutes,so it's more like they are asking you to find how far the swimmer can swim in 30minutes

50.2-1min

x -30min

x=50.2×30

x=1506meters

6 0

2 years ago

Read 2 more answers

Which is a true statement about the line x − 4y = 8?

Vedmedyk [2.9K]

The y-intercept of the line is (0, -2), the x-intercept is (8, 0). the slope of the line is in fact 1/4

so your answer is C.

hope this helps, God bless!

8 0

2 years ago

From the equation 5 - 4 + 7x + 1 = __x + __, use numbers 0 - 9 to find No Solutions, One Solution, or Infinitely Many Solutions.

mina [271]

The correct answer is

5 - 4 + 7x + 1 = 7 x + 1

5 0

2 years ago