A bag contains four red marbles, two Yellow Marbles and five blue marbles.
Two marbles are drawn at random without replacement.
Total number of marbles are,
There are 11 ways to select first marble and 10 ways to select second marble.
The total number of possible outcomes are calculated as,
Thus the total number of possible outcomes are 110.
<u>Anna:</u>
1st month = 18 + = 18
inches
2nd month = 18 +
= 19
3rd month = 19 +
= 20
4th month = 20 +
= 21
5th month = 21 + = 21
<u>Grace:</u>
Because Anna is inches shorter than Grace, we can start the count from the third month:
1st month = 20
2nd month = 21
3rd month = 21
4th month = 21 +
= 22
5th month = 22 +
= 23
Answer:
21
Step-by-step explanation:
Using<em> Simple Random Sampling</em>, we can estimate the sample size by the formula
where
n = sample size
Z = the z-score corresponding to the confidence level 99.5%
S = the assumed standard deviation = 3 seconds
e = margin of error = 2 seconds
<em>It is worth noticing that the higher the confidence level, the larger the sample should be. </em>
The z-score corresponding to a confidence level of 99.5% can be obtained either with a table or the computer and equals
Z = 3.023
Replacing the values in our formula
So the size of the sample should be at least 21.