20) Answer is: x=76
21) Answer is x=15
Answer:
Step-by-step explanation:
Hello!
X: number of absences per tutorial per student over the past 5 years(percentage)
X≈N(μ;σ²)
You have to construct a 90% to estimate the population mean of the percentage of absences per tutorial of the students over the past 5 years.
The formula for the CI is:
X[bar] ±
* 
⇒ The population standard deviation is unknown and since the distribution is approximate, I'll use the estimation of the standard deviation in place of the population parameter.
Number of Absences 13.9 16.4 12.3 13.2 8.4 4.4 10.3 8.8 4.8 10.9 15.9 9.7 4.5 11.5 5.7 10.8 9.7 8.2 10.3 12.2 10.6 16.2 15.2 1.7 11.7 11.9 10.0 12.4
X[bar]= 10.41
S= 3.71

[10.41±1.645*
]
[9.26; 11.56]
Using a confidence level of 90% you'd expect that the interval [9.26; 11.56]% contains the value of the population mean of the percentage of absences per tutorial of the students over the past 5 years.
I hope this helps!
The answer is 588 because if you multiply 6.75 percent of 4800 by 13, and then subtract it from 4800, you get 588.
C. -3,-3 is the correct answer
Answer:
2.5 m
Step-by-step explanation:
Consider the ramp, the ground and the back of the lorry to form a right triangle where the ramp is the hypotenuse and the distance from the back of the lorry is the adjacent side, x
Using the cosine ratio in the right triangle
cos32° =
= 
Multiply both sides by 3
3 × cos32° = x, hence
x ≈2.5 m