Meg has 26 toy ponies.She gets 6 more for her birthday.She displays half of them on a shelf and puts the rest in a box.How many
2 answers:
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Answer:
A 90% confidence interval for the mean BAC in fatal crashes in which the driver had a positive BAC is [0.143, 0.177] .
Step-by-step explanation:
We are given that a researcher randomly selects records from 60 such drivers in 2009 and determines the sample mean BAC to be 0.16 g/dL with a standard deviation of 0.080 g/dL.
Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;
P.Q. = ~
where, = sample mean BAC = 0.16 g/dL
s = sample standard deviation = 0.080 g/dL
n = sample of drivers = 60
= population mean BAC in fatal crashes
<em>Here for constructing a 90% confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation. </em>
So, a 90% confidence interval for the population mean, is;
P(-1.672 < < 1.672) = 0.90 {As the critical value of t at 59 degrees of
freedom are -1.672 & 1.672 with P = 5%} P(-1.672 < < 1.672) = 0.90
P( <
<
) = 0.90
P( <
<
) = 0.90
<u>90% confidence interval for</u> = [
,
]
= [ ,
]
= [0.143, 0.177]
Therefore, a 90% confidence interval for the mean BAC in fatal crashes in which the driver had a positive BAC is [0.143, 0.177] .
Answer:
a) For this case we define the random variable X="number of car owners in a random sample of 12 who get the maintenance service done on their cars according to the schedule recommended by the auto company". And for this case the distribution for X is:
And the possible values for the random variable are X=0,1,2,3,4,5,6,7,8,9,10,11,12
b) Using the probability mass function we got:
Step-by-step explanation:
Previous concepts
A Bernoulli trial is "a random experiment with exactly two possible outcomes, "success" and "failure", in which the probability of success is the same every time the experiment is conducted". And this experiment is a particular case of the binomial experiment.
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
Solution to the problem
Part a
For this case we define the random variable X="number of car owners in a random sample of 12 who get the maintenance service done on their cars according to the schedule recommended by the auto company". And for this case the distribution for X is:
And the possible values for the random variable are X=0,1,2,3,4,5,6,7,8,9,10,11,12
Part b
Find to 3 decimal places the probability that exactly 3 car owners in a random sample of 12 get the maintenance service done on their cars according to the schedule recommended by the auto company.
Using the probability mass function we got: