Write an expression for the sequence of operations described below .
1 answer:
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The temperature was changing at a rate of 2.925 degrees Celsius in 2005
<h3>How to determine the rate in 2005</h3>From the graph (see attachment), we have the following ordered pair
(x,y) = (5,14.625)
The above means that, the temperature in 2005 is 14.625 degrees Celsius
So, the rate in 2005 is:
Hence, the temperature was changing at a rate of 2.925 degrees Celsius in 2005
Read more about average rates at:
Answer:
The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 20 - 1 = 19
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 19 degrees of freedom(y-axis) and a confidence level of . So we have T = 1.7291
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample. For this question, we have . So
The margin of error of the 90% confidence interval of a student's average typing speed is of 1.933 wpm.
Answer:
Null hypothesis:
Alternative hypothesis:
Step-by-step explanation:
1) Data given and notation
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
2) State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the mean is higher than 8000, the system of hypothesis are :
Null hypothesis:
Alternative hypothesis:
Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:
(1)
z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
3) Calculate the statistic
We can replace in formula (1) the info given like this:
4) P-value
Since is a one-side upper test the p value would given by:
5) Conclusion
If we compare the p value and the significance level assumed, for example we see that
so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the mean is significantly higher than $8000.