What two numbers multiply to 30 and add to -17
1 answer:
You might be interested in
Answer:
x = 4
y = -3
Step-by-step explanation:
We can use substitution, elimination, or graphically.
Step 1: Rearrange first equation
2x + 4y = -4
2x = -4 - 4y
x = -2 - 2y
Step 2: Rewrite systems of equations
x = -2 - 2y
3x + 5y = -3
Step 3: Substitution
3(-2 - 2y) + 5y = -3
-6 - 6y + 5y = -3
-6 - y = -3
-y = 3
y = -3
Step 4: Find <em>x</em> using <em>y</em>
2x + 4(-3) = -4
2x - 12 = -4
2x = 8
x = 4
Graphically:
Use a graphing calc and analyze where the 2 lines intersect.
<h2>Answer with explanation:</h2>
Let be the average starting salary ( in dollars).
As per given , we have
Since is left-tailed , so our test is a left-tailed test.
WE assume that the starting salary follows normal distribution .
Since population standard deviation is unknown and sample size is small so we use t-test.
Test statistic : , where n= sample size ,
= sample mean , s = sample standard deviation.
Here , n= 15 , , s= 225
Then,
Degree of freedom = n-1=14
The critical t-value for significance level α = 0.01 and degree of freedom 14 is 2.62.
Decision : Since the absolute calculated t-value (2.07) is less than the critical t-value., so we cannot reject the null hypothesis.
Conclusion : We do not have sufficient evidence at 1 % level of significance to support the claim that the average starting salary of the graduates is significantly less that $42,000.