Answer:
22
Step-by-step explanation:
Find f(-3) :
f(x) = x² + 2x for x ≤ -3
That means for those values of x, less than or equal to -3, this is the function.
So, f(-3) = (-3)² + 2(-3) = 9 - 6 = 3
Now, f(-1) :
From the given data, we see it is: f(x) = 2
We take this because -1 lies between -3 and 4.
Now, f(-1) = 2
=>
For f(4) :
Clearly, the function is:
Therefore, <u>f(-3) + f(-1) - f(4) = 3 + 18 - (-1) = 3 + 18 + 1 = 22.</u>
Answer: No , at 0.05 level of significance , we have sufficient evidence to reject the claim that LTCC Intermediate Algebra students get less than seven hours of sleep per night, on average.
Step-by-step explanation:
Let denotes the average hours of sleep per night.
As per given , we have
, since is left-tailed and population standard deviation is unknown, so the test is a left-tailed t -test.
Also , it is given that ,
Sample size : n= 22
Sample mean :
Sample standard deviation : s= 1.93
Test statistic :
i.e.
For significance level and degree of freedom 21 (df=n-1),
Critical t-value for left-tailed test=
Decision : Since the test statistic value (0.58) > critical value 1.7207, it means we are failed to reject the null hypothesis .
[Note : When , then we accept the null hypothesis.]
Conclusion: We have sufficient evidence to reject the claim that LTCC Intermediate Algebra students get less than seven hours of sleep per night, on average.