Answer:
See below
Step-by-step explanation:
To construct a confidence interval we use the following formula:
ci = (sample mean) +- z*(sd)/[n^(1/2)]
The sample mean is 57, the standard deviation is 2.36, n s 25 and z is the upper (1-C)/2 critical value for the standard normal distribution. Here, as we want a confidence interval at a 90% we have (1-C)/2=0.05 we have to look at the 1-0.05=0.95 value at the normal distribution table, which is 1.65 approximately. Replacing all these values:
ci = 57 +- 1.65*(2.36)/[25^(1/2)]
ci = 57 +- 3.894*/(5) = 57 +- 0.78
ci => (56.22 , 57.78)
Answer:
59 degrees
Step-by-step explanation:
180 - 126 = 54
6x-1 + 5x + 17 +54 =180
11x + 70 = 180
11x = 180 -70
11x = 110
x =10
Therefore
6(10) - 1 = 59 degrees
Answer:
$100
Step-by-step explanation:
Hewooo
the picture below should help you :>
Answer:
The probability that a call last between 4.2 and 4.9 minutes is 0.4599
Step-by-step explanation:
Let X be the length in minutes of a random phone call. X is a normal distribution with mean λ=4.2 and standard deviation σ=0.4. We want to know P(4.2 < X < 4.9). In order to make computations, we will use W, the standarization of X, given by the following formula
We will use 
, the cummulative distribution function of W. The values of are well known and the can be found in the attached file
We conclude that the probability that a call last between 4.2 and 4.9 minutes is 0.4599
