In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes. A telephone company wants to perform a test to determine whether this average duration of long- distance calls has changed. Fifty calls, originating from the town, was randomly selected and the following summary minutes. Σx= 205 E(x - x)? = 56.43 a) Calculate the sample mean, x. b) Calculate the sample standard deviation c) Using the p value approach at the 1% level of significance, test whether the mean duration of long-distance calls from the town had increased. d) Construct the 99% confidence interval for the population mean duration of the long-distance calls from the town.
Family of Curves
A family of curves is a group of curves that are each described by a parametrization in which one or more variables are parameters. In general, the parameters have more complexity on the assembly of the curve than an ordinary linear transformation. These families appear commonly in the solution of differential equations. When a constant of integration is added, it is normally modified algebraically until it no longer replicates a plain linear transformation. The order of a differential equation depends on how many uncertain variables appear in the corresponding curve. The order of the differential equation acquired is two if two unknown variables exist in an equation belonging to this family.
XZ Plane
In order to understand XZ plane, it's helpful to understand two-dimensional and three-dimensional spaces. To plot a point on a plane, two numbers are needed, and these two numbers in the plane can be represented as an ordered pair (a,b) where a and b are real numbers and a is the horizontal coordinate and b is the vertical coordinate. This type of plane is called two-dimensional and it contains two perpendicular axes, the horizontal axis, and the vertical axis.
Euclidean Geometry
Geometry is the branch of mathematics that deals with flat surfaces like lines, angles, points, two-dimensional figures, etc. In Euclidean geometry, one studies the geometrical shapes that rely on different theorems and axioms. This (pure mathematics) geometry was introduced by the Greek mathematician Euclid, and that is why it is called Euclidean geometry. Euclid explained this in his book named 'elements'. Euclid's method in Euclidean geometry involves handling a small group of innately captivate axioms and incorporating many of these other propositions. The elements written by Euclid are the fundamentals for the study of geometry from a modern mathematical perspective. Elements comprise Euclidean theories, postulates, axioms, construction, and mathematical proofs of propositions.
Lines and Angles
In a two-dimensional plane, a line is simply a figure that joins two points. Usually, lines are used for presenting objects that are straight in shape and have minimal depth or width.
![In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes.
A telephone company wants to perform a test to determine whether this average duration of long-
distance calls has changed. Fifty calls, originating from the town, was randomly selected and the
following summary minutes.
Σχ= 205
E(x – x)? = 56.43
a) Calculate the sample mean, x.
b) Calculate the sample standard deviation
c) Using the p value approach at the 1% level of significance, test whether the mean duration of
long-distance calls from the town had increased.
d) Construct the 99% confidence interval for the population mean duration of the long-distance
calls from the town.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fa6cbb78b-8cd9-42d3-9f25-d0b5e07bd270%2Fff5bab03-ecbb-4ff2-9548-ba168e78eddf%2Ftkeyxja_processed.jpeg&w=3840&q=75)
![A random sample of residents from various income brackets were asked their opinion on tax reform
for the country of Guyana. The data so gathered were analyzed by a statistician and the results he
obtained using MINITAB are shown below:
Expected counts are printed below observed counts
Low
Middle
High
Total
For
26
75
14
115
(30.67)
(51.11)
(33.22)
Against
60
95
105
260
(69.33)
(115.56)
(**)
Neutral
34
30
11
75
(33.33)
200
(20)
(21.67)
Total
130
450
Chi-sq =
0.71 +
11.17 +
11.12 +
3.66 +
0.33 +
*** +
11.89 +
9.8 +
5.25 =
55.2
DF = ??, p-value =???
a) Carefully define the null and alternative hypotheses of the x2 test underlying the generation
of the above table.
b) Find the missing values *, **, *****, ??" and ???'.
c) What is the conclusion of this test? Give reasons for your answer.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fa6cbb78b-8cd9-42d3-9f25-d0b5e07bd270%2Fff5bab03-ecbb-4ff2-9548-ba168e78eddf%2Fnewz7fu_processed.jpeg&w=3840&q=75)
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