The random variable X is exponentially distributed, where X represents the time it takes for a person to choose a birthday gift.
1 answer:
Answer:
0.685 = 68.5% probability that X is less than 30 minutes
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:
In which is the decay parameter.
The probability that x is lower or equal to a is given by:
Which has the following solution:
If X has an average value of 26 minutes
This means that
What is the probability that X is less than 30 minutes?
0.685 = 68.5% probability that X is less than 30 minutes
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There are several ways to find the angle at A.
One is to realize the bisector of angle A will make a right angle with BC, creating two congruent triangles with short leg 2 and hypotenuse 7. Then the sine of the half-angle at A will be 2/7, so
A = 2*arcsin(2/7)
A ≈ 2*16.6015° = 33.203°
The measure of the angle at A to the nearest degree is
33°
_____
Another way to find the angle is to use the Law of Cosines. After solving for the angle (A) in terms of sides a, b, c, you find
A = arccos((b²+c²-a²)/(2bc)) = arccos(7²+7²-4²)/(2*7*7))
A = arccos(82/98) ≈ 33°
And you can always use a triangle solver application.
One is to realize the bisector of angle A will make a right angle with BC, creating two congruent triangles with short leg 2 and hypotenuse 7. Then the sine of the half-angle at A will be 2/7, so
A = 2*arcsin(2/7)
A ≈ 2*16.6015° = 33.203°
The measure of the angle at A to the nearest degree is
33°
_____
Another way to find the angle is to use the Law of Cosines. After solving for the angle (A) in terms of sides a, b, c, you find
A = arccos((b²+c²-a²)/(2bc)) = arccos(7²+7²-4²)/(2*7*7))
A = arccos(82/98) ≈ 33°
And you can always use a triangle solver application.
Answer:
The degrees of freedom are given by:
The p value for this case is given by:
For this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 200 F.
Step-by-step explanation:
Information given
data: 202.2 203.4 200.5 202.5 206.3 198.0 203.7 200.8 201.3 199.0
We can calculate the sample mean and deviation with the following formulas:
represent the sample mean
represent the sample standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
t would represent the statistic
represent the p value for the test
Hypothesis to test
We want to determine if the true mean is equal to 200, the system of hypothesis are :
Null hypothesis:
Alternative hypothesis:
The statistic for this case is given by:
(1)
The statistic is given by:
The degrees of freedom are given by:
The p value for this case is given by:
For this case since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly different from 200 F.