Answer:

Step-by-step explanation:
The reciprocal of a number n is 
Given 8
, change to an improper fraction
=
=
, thus
reciprocal =
= 
0.843 that should be rounded from the nearest 100th
Answer:

And using the cumulative distribution function we got:

The probability that preparation is within 2 minutes of the mean time is 0.134
Step-by-step explanation:
For this case we define the following random variable X= (minutes) for a lab assistant to prepare the equipment for a certain experiment , and the distribution for X is given by:

The cumulative distribution function is given by:

The expected value is given by:

And we want to find the following probability:

And we can find this probability on this way:

And using the cumulative distribution function we got:

The probability that preparation is within 2 minutes of the mean time is 0.134
Answer:
She used the simple random sampling technique because there was no condition attached to the samples she took.
Step-by-step explanation:
we have basically four types of sampling
1.Simple random sampling.
2.Systematic sampling.
3.Stratified sampling.
4.Cluster sampling.
simple Random sampling: is a sampling technique where every item in the population has an even chance and likelihood of being selected in the sample.