1. Which of the following expressions is equivalent to -3(x + 2) + (x – 3)x:
2 answers:
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Answer: Mary need to make at-least 95 on her fourth test to earn an A in her algebra course.
Step-by-step explanation:
Let x be the grades scored by Mary in the fourth algebra test.
Mary has grades of 95, 82, 88 on her first three algebra tests.
Then, the combined scores in four test will become = 95+82+88+x = 265+x
Average score = (Sum of all scores) ÷ (Number of tests)
As per given ,
To earn an A in an algebra course, a student must have a test average of at least 90.
i.e. Average score ≥ 90
Hence, Mary need to make at-least 95 on her fourth test to earn an A in her algebra course.
Answer:
The degrees of freedom are given by:
And the p value would be:
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 higher than 2.3 ppm the safe limit
Step-by-step explanation:
Information provided
represent the sample mean in ppm
represent the sample standard deviation
sample size
represent the value to verify
represent the significance level
t would represent the statistic
represent the p value
System of hypothesis
We want to verify if the true mean is higher than 2,3 ppm, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic for this case is given by:
(1)
Replacing the info given we got:
The degrees of freedom are given by:
And the p value would be:
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 higher than 2.3 ppm the safe limit