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Statss
The normal (gaussian) distribution
Which statement is a property of probability
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Questions
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Answers
1
Which statement is a property of probability
-1 < P(A) < 1
0 ≤ P(A) ≤ 1
(- infinito) < P(A) < (+ infinito)
0 < P(A) < 1
2
The normal (gaussian) distribution
Continuous random variables.
Both random variables.
Discrete random variables.
None
3
Prove the formula DX = MX
2
– (MX)
2
MX = ∫ (x-MX)2 · f(x) dx
MX = ∫ x · f(x) dx
MX = ∫ x2 · f(x) dx
None
4
Which statement is true about population and sample characteristics
D
C
B
A
5
????
No correct answer. Correct answer is 0
0,3
1
0,2
6
Which formula is multiplicative rule
P(A· B) = P (B) · P(A)
P(A· B) = P (A/B)
P(A· B) = P (A) · P(B)
P(A· B) = P (A) * P (B/A)
7
Which numerical characteristics is a characteristics of scatter
Mean
Dean
None
Variance
8
Density funtion f(x) is use to express a distribution of
Density function is no used
Discrete random variable
Both random variables
Continuous random variable
9
If two variables X and Y are independent
-1< Pxy <1
Pxy = -1
Pxy = 0
Pxy = 1
10
quantile of studnts distribution for equality of means of two independnt prportions depends on
P=0.95, f=n-1
P=(1+p)/2, f= n1+n2-2
P=0.95, f=n1+n2-2,
P=(1+p)/2, f=n-1
11
X
2
test are used when
A
C
D
B
12
Wht are totality of people, othr living orgnisms or inanimate objcts undr study in stats called
people
Population
society
community
13
Histogram is used to show
The distribution of features in sample
The distribution of mean and variance in sample
The distribution of features in population
The distribution of mean and variance in population
14
The length of a confidence interval depends on
Sample size and confidence level.
Sample size only
None
Confidence level only.
15
Which sentence is a definition of probability of an event A:
C
D
A
B
16
The test statistics is
A number which shows the strength of type I error.
A rule by which we decide the null hypothesis is true or not
A criteria according to which we find a critical value
A rule by which we find minimum sample size
17
Which property for variance of random variable is not right
D Cx = C² DX
All are right
D (x ± y)= Dx ± Dy
D (c) = 0
18
There is a statistic significant difference between the variance of two proportions if
F>Fp
F≥ Fp
F< Fp
F≤ Fp
19
Null hypothesis is
C
A
B
20
If a coin is flipped 7 times, what is the probability that head will appear 4 times?
0.5
0.871
0.28
0.07
21
Is Ho rejected while indeed it is true
Sample size is not small
Confidence level is too big
Type I error
Type II error
22
In formula of total probability events A an Ā
Independent events
Dependent events
Mutually exclusive events
Any events
23
Which property is not for function of distribution F (x)
0 ≤ F (x) ≤ 1
P (a ≤ x < b) = F (b) – F (a)
P (a ≤ x < b) = S (entre a y b ) f(x) dx
P (a ≤ x < b) = F (b) – F (a)
24
If variables X and Y are independent, then their regression lines
None
Are perpendicular to each other
Intersect and acute angle
It is impossible to draw their regression lines
25
If two events are mutually exclusive, they
are independent
are dependent
can happen together
cannot happen together
26
A population is:
D
C
B
A
27
Which statement about density function is right
F(x) = S(entre menos infinito y x) f (u) du
F (x) = P
F (X)= f(x)
There is no right answer
