The temperature of a cup of coffee changed by –54 degrees Celsius over 22 ½ minutes. What was the change in temperature each mi
2 answers:
You might be interested in
Answer:
a)
The null hypothesis is
The alternative hypothesis is
b-1) The value of the test statistic is t = 1.86.
b-2) The p-value is of 0.0348.
Step-by-step explanation:
Question a:
Test if the battery life is more than twice of 5 hours:
Twice of 5 hours = 5*2 = 10 hours.
At the null hypothesis, we test if the battery life is of 10 hours or less, than is:
At the alternative hypothesis, we test if the battery life is of more than 10 hours, that is:
b-1. Calculate the value of the test statistic.
The test statistic is:
We have the standard deviation for the sample, so the t-distribution is used to solve this question
In which X is the sample mean, is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.
10 is tested at the null hypothesis:
This means that
In order to test the claim, a researcher samples 45 units of the new phone and finds that the sample battery life averages 10.5 hours with a sample standard deviation of 1.8 hours.
This means that
Then
The value of the test statistic is t = 1.86.
b-2. Find the p-value.
Testing if the mean is more than a value, so a right-tailed test.
Sample of 45, so 45 - 1 = 44 degrees of freedom.
Test statistic t = 1.86.
Using a t-distribution calculator, the p-value is of 0.0348.
Answer:
B
Step-by-step explanation:
One good way to look at this is to graph both polynomials, as shown in the picture. A tip to help graph is to factor it out and work from there. For example, in x²+14x+48, we can gather that (x+6)(x+8) is the same thing, and it is easier to then graph it. Similarly, for x²+12x+36, we can factor it out as (x+6)² .
When x²+12x+36 approaches 6, it is getting really close to 0, but it stays positive. When x²+14x+48 approaches 6 from the negative side, it is also getting close to 0, but it's negative. When x²+14x+48 approaches 6 from the positive side, it is positive.
Therefore, on the negative side, there is one positive and one negative (dividing a negative by a positive is negative, and a positive by a negative is also negative) , and on the positive side, there are two positives, forming one answer.The answer is therefore B
