As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:

$\sigma_{\bar{x}}\approx\frac{s}{\sqrt{n}}$

The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.

The mean of the sample is:

$\bar{x}=\frac{1}n} \sum x_i =\frac{30+40+60+80+20+85}{6}=52.5$

The standard deviation of the sample is calculated as:

$s=\sqrt{\frac{1}{n-1}\sum (x_i-\bar x)^2} \\\\ s=\sqrt{\frac{1}{5}\cdot ((30-52.5)^2+(40-52.5)^2+(60-52.5)^2+(80-52.5)^2+(20-52.5)^2+(85-52.5)^2}\\\\s=\sqrt{\frac{1}{5} *3587.5}=\sqrt{717.5}=26.8$

Then, we can calculate the standard error of the mean as:

$\sigma_{\bar{x}}\approx\frac{s}{\sqrt{n}}=\frac{26.8}{6}= 4.5$

6 0

3 years ago

True [87]

Answer:

D. RWS and SWT

Step-by-step explanation:

Adjacent angles have a common side and a common vertex but they don't overlaps each other

The two angles that has these requirements are :

RWS and SWT

8 0

3 years ago

Read 2 more answers

Determine the perimeter of the triangle.<br> 3x<br> x + 6<br> 5x – 7

Gekata [30.6K]

Answer:

9x-1

Step-by-step explanation:

The perimeter of the triangle is adding up all 3 sides.

(3x)+(x+6)+(5x-7)=P

9x-1 = perimeter

All I have done is combine like terms.

If there is a... x = something, replace x with the number.

8 0

3 years ago

Jones deposits $15,000 in an account that earns 6% interest,​

Jones deposits $15,000 in an account that earns 6% interest,