Aubree wanted to see if there is a connection between the time a given exam takes place and the average score of this exam. She
2 answers:
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Answer:
B) P(two prime numbers are drawn in a row) = 14/95
Step-by-step explanation:
Total cards in the deck = 20
Total prime numbered cards in deck = { 2, 3, 5, 7, 11, 13, 17, 19} = 8 cards
So, Probability of picking two prime cards from deck (without replacing)
= Probability of picking first prime card x Probability of picking second prime card
P( picking first prime card ) =
=
P( picking second prime card ) =
=
Hence, the total probability =
or, B) P(two prime numbers are drawn in a row) = 14/95
Answer:
So on this case the 95% confidence interval would be given by (11.393;15.857)
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Data: 14, 10, 13, 16, 12, 18, 15, 11
We can calculate the sample mean and deviation with the following formulas:
represent the sample mean
population mean (variable of interest)
s=2.669 represent the sample standard deviation
n=8 represent the sample size
Calculate the confidence interval
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value we need to find first the degrees of freedom, given by:
Since the confidence is 0.95 or 95%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,7)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 95% confidence interval would be given by (11.393;15.857)