Will mark brainliest, please answer correctly!!!
1 answer:
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Answer:
Step-by-step explanation:
First we need to make sure that the leading coefficient is a 1. Ours is a 4, so we need to factor it out, leaving us with
To complete the square, take half the linear term, square it, then add it to both sides. But don't forget about that 4 hanging around out front, refusing to be ignored. Our linear term is 18. Half of 18 is 9, and 9 squared is 81. Add 81 into the parenthesis, but what we REALLY added in was 4*81 which is 324:
To solve this, we need to get the x terms all by themselves. So let's divide both sides by 4 to get
The process of completing the square created a perfect square binomial on the left. We will state this binomial now:
We isolate the x term by taking the square root of both sides:
x - 9 = ±9
From that we have 2 equations:
x - 9 = 9 and x - 9 = -9
Which means that x = 18 or x = 0
Answer:
There is no significant improvement in the scores because of inserting easy questions at 1% significance level
Step-by-step explanation:
given that Montarello and Martins (2005) found that fifth grade students completed more mathematics problems correctly when simple problems were mixed in with their regular math assignments. To further explore this phenomenon, suppose that a researcher selects a standardized mathematics achievement test that produces a normal distribution of scores with a mean of µ= 100 and a standard deviation of σ = 18. The researcher modifies the test by inserting a set of very easy problems among the standardized questions and gives the modified test to a sample of n = 36 students.
Set up hypotheses as
(right tailed test at 1% level)
Mean difference = 104-100 =4
Std error of mean =
Since population std deviation is known and also sample size >30 we can use z statistic
Z statistic= mean diff/std error = 1.333
p value = 0.091266
since p >0.01, we accept null hypothesis.
There is no significant improvement in the scores because of inserting easy questions at 1% significance level