Answer:
a) x = 80.40
s = 29.54
b) lower limit = 69.53
upper limit = 91.27
Step-by-step explanation:
The mean price is:
The standard deviation is
![s=\sqrt{\frac{1}{n-1}\sum(x_i-\bar X)^2}=\sqrt{\frac{1}{19}[(50-80.4)^2+...+(70-80.4)^2]} \\\\s=\sqrt{\frac{15,471}{19} }=\sqrt{814.25} =29.54](https://tex.z-dn.net/?f=s%3D%5Csqrt%7B%5Cfrac%7B1%7D%7Bn-1%7D%5Csum%28x_i-%5Cbar%20X%29%5E2%7D%3D%5Csqrt%7B%5Cfrac%7B1%7D%7B19%7D%5B%2850-80.4%29%5E2%2B...%2B%2870-80.4%29%5E2%5D%7D%20%5C%5C%5C%5Cs%3D%5Csqrt%7B%5Cfrac%7B15%2C471%7D%7B19%7D%20%7D%3D%5Csqrt%7B814.25%7D%20%3D29.54)
We have to calculate a 90% CI for the mean.
The z-value for a 90% confidence interval is z=1.645.
The margin of error is:
The 90% CI is
Answer:
3
Step-by-step explanation:
Answer:
3x^2 + 2x
Step-by-step explanation:
Answer:
I am not sure about the actual answer but hopefuly you figure this out
Step-by-step explanation:
To get the number of boys and girls you do 3+5 to get 8. 120 divided by 8 is 15. so every digit in the ratio is 15 students. 15x3 is 45 and 15x5 is 75. there are 45 girls and 75 boys. 16/25 of the boys go climbing. There are 75 boys so you do 16x3 because 25x3 is 75 so 16x3 is 48. 48 boys go climbing. 120-48 is 72. and 27 boys go sailing.
