Answer:
Grade A: 
Grade B: 
Grade C: 
Grade D: 
Step-by-step explanation:
Problems of normally distributed samples can be solved using the Z score table.
The Z score of a measure represents how many standard deviations it is above or below the mean of all the measures.
Each Z score has a pvalue. This represents the percentile of the measure.
In this problem, we have that:
The upper 16% of the class get A grades. The upper 16% has a pvalue of at least 100% = 16% = 84% = 0.84. This is
.
The middle 34% of the class get B grades. The middle 34% has a pvalue of at least 84%-35% = 50% = 0.5 and at most 0.84. This is
.
Those between a pvalue of 0.5-0.34 = 0.16 and 0.5 get get grade C.
has a pvalue of 0.16. So a grade C is in the interval
.
Those with Z lesser than -1 get grades D and F
Answer:
The length of each leg = 5 units
The length of the base = 4 units
Step-by-step explanation:
Isosceles Triangle is a triangle with any two sides of it in equal measure.
Perimeter of a triangle = SUM OF ALL SIDES
Now, Perimeter of the triangle = 14
Let length of each leg = a
So, the length of the other leg is also a.
And, the base of the triangle is a -1
Now, as perimeter is 14.
⇒a + a + (a -1) = 14
or, 3 a = 14 + 1
⇒ 3 a = 15, or a = 15/3 = 5
Hence, the length of each leg = 5
And the length of the base = (a -1) = (5-1) = 4 units
Answer:
a. We reject the null hypothesis at the significance level of 0.05
b. The p-value is zero for practical applications
c. (-0.0225, -0.0375)
Step-by-step explanation:
Let the bottles from machine 1 be the first population and the bottles from machine 2 be the second population.
Then we have
,
,
and
,
,
. The pooled estimate is given by
a. We want to test
vs
(two-tailed alternative).
The test statistic is
and the observed value is
. T has a Student's t distribution with 20 + 25 - 2 = 43 df.
The rejection region is given by RR = {t | t < -2.0167 or t > 2.0167} where -2.0167 and 2.0167 are the 2.5th and 97.5th quantiles of the Student's t distribution with 43 df respectively. Because the observed value
falls inside RR, we reject the null hypothesis at the significance level of 0.05
b. The p-value for this test is given by
0 (4.359564e-10) because we have a two-tailed alternative. Here T has a t distribution with 43 df.
c. The 95% confidence interval for the true mean difference is given by (if the samples are independent)
, i.e.,
where
is the 2.5th quantile of the t distribution with (25+20-2) = 43 degrees of freedom. So
, i.e.,
(-0.0225, -0.0375)
Answer:
960cm³ (D)
Step-by-step explanation:
A plastic box is in form of a cuboid.
The volume of a cuboid = Length × Breadth × Height
Given the dimension 15cm by 8cm by 8cm
Length = 15cm
Breadth = 8cm
Height = 8cm
Volume of the plastic box = 15×8×8
= 960cm³ D