### Simple moving average - class-X

 Description: simple moving average Number of Questions: 15 Created by: Kalki Agrawal Tags: analyzing data time series and forecasting time series maths moving averages statistics
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A train running at $\dfrac{7}{{11}}$ of its own speed reached a place in 22 hours. How much time could be saved if the train would have run at its own speed ?

1. 7 hours

2. 8 hours

3. 14 hours

4. 16 hours

Correct Option: B
Explanation:
Let s be the actual speed of the train and d be the distance that needs to be covered to reach that place.

Here, speed$=\dfrac{Distance}{Time}$

As per question,

The train is running at $\dfrac{7}{11}$ of its own speed and reaches the place in $22$ hrs.

$\therefore d=\dfrac{7}{11}s.22$

$\Rightarrow d=14s$ ………..$(1)$

Let t be the time taken by the train to reach the place with its actual speed.

$\therefore d=st$ ………..$(2)$

from $(1)$ and $(2)$, we get

$14s=st$

$\Rightarrow t=14$ hours

$\therefore$ Time that could be saved$=22-14$

$=8$hrs.

The total numbers of squares on a chessboard is

1. $206$

2. $205$

3. $204$

4. $202$

Correct Option: C
Explanation:

From Permutation and Combination,

no. of squares of 1x1 $=1^2$
no. of squares of 2x2 $=2^2$
no. of squares of 3x3$=3^2$
.
.
.
no. of squares of 8x8 $=8^2$

Hence Total number of squares $=1^2+2^2+......+8^2$
$\implies 204$

The average weight of $A,B,C$ is $45kg$ . If the average weight of $A$ and $B$ be $40kg$ and that of $B$ and $C$ be $43kg$, find the weight of $B$ ?

1. $21kg$

2. $20kg$

3. $38kg$

4. $31kg$

Correct Option: D
Explanation:

$\cfrac{A+B+C}{3}=45$ $kg$

$\Rightarrow A+B+C=45\times3=135$ $kg$
$\Rightarrow \cfrac{A+B}{2}=40$ $kg$
$\Rightarrow A+B=80$ $kg$
$\therefore C=135-80=55$ $kg$
$\Rightarrow \cfrac{B+C}{2}=43$ $kg$
$\Rightarrow B+C=86$ $kg$
$\therefore B=86-55=31$ $kg$
$\therefore$ The weight of $B$ is $31$ $kg$.

In a call of 100 students there are 70 boys whose average marks in a subject is 75. If the average marks of the complete class is 72 . then the average marks of the girls is

1. 73

2. 65

3. 68

4. 74

Correct Option: B
Explanation:
Total student = 100
For 70 students total marks = 75×7075×70
=5250=5250
Total marks of girls = & 7200-5250$=1950=1950 Average of girls = 195030195030 =65 .Twelve years hence a man will be four times as he was twelve years ago, then his present age is 1. 20 years 2. 25 years 3. 28 years 4. 30 years Correct Option: A Explanation: Let his present age be x According to problem x + 12 = 4 (x - 12) -3x = - 48 - 12 3x = 60 x = 20 years David obtained 76,65,82,67,and 85 marks(out of 100) in English,Mathematics,Physics,Chemistry and Biology.What are his average marks? 1. 75 2. 69 3. 72 4. 76 Correct Option: A Explanation: Average is equal to the sum of marks of all the subjects by the total number of subjects.$\therefore Avg=\dfrac{76+65+82+67+85}{5}=75$Moving-averages: 1. Give the trend in a straight line 2. Measure the seasonal variations 3. Smooth-out the time series 4. None of them Correct Option: C Explanation:$\Rightarrow$Moving-averages :$Smooth-out\,the\,time\,series$.$\Rightarrow$A moving average is a widely used indicator in technical analysis that helps smooth out price action by filtering out the “noise” from random price fluctuations.$\Rightarrow$It is a trend-following, or lagging, indicator because it is based on past prices. The average weight of 10 men is decreased by 3 kg when one of them whose weight is 80 kg is replaced by a new person. The weight of the new person is 1. 70 2. 60 3. 50 4. 73 Correct Option: C Explanation: Let weight of$9$men$=x$. Weight of new men$=y$According to the question,$\dfrac{x+80}{10}-3=\dfrac{x+y}{10}\dfrac{x+80-30}{10}=\dfrac{x+y}{10}x+50=x+yy=50\ kg$Hence, this is the answer. The problem given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statements(s) is / are necessary to answer the question. How many marks did Tarun secure in English? (i)The average marks obtained by Tarun in four subjects including English are 60. (ii) The total marks obtained by him in English and Mathematics together are 170. (iii)The total marks obtained by him in Mathematics and science together are 180. 1. I and II only 2. II and III only 3. I and III only 4. None of these Correct Option: D Explanation: These statements are not enough to find out his English marks. So Ans = D Choose the correct answer from the alternatives given. A man covers a distance of$160$km at$64 km/hr$and next$160$km at$80 km/hr$. What is his average speed for his whole journey of$320$km? 1.$73.00km/h$2.$71.11km/h$3.$70.50km/h$4.$72.25km/h$Correct Option: B Bira and his wife Sheena have two daughters aged$12$and$16$. Sheena's mother and father, aged$65$and$72$, also live with them. Bira is currently looking for work, but can't find any. His elder daughter completed class$10$and prefers to look for work. Sheena prefers to stay at home to look after house works. How many unemployed members does Bira's family have? 1.$1$2.$2$3.$3$4.$4$Correct Option: B Explanation: Only Bira and his elder daughter can be called unemployed as per the given situation. A qualitative forecast 1. predicts the quality of a new product. 2. predicts the direction, but not the magnitude, of change in a variable. 3. is a forecast that is classified on a numerical scale from$1$(poor quality) to$10$(perfect quality). 4. is a forecast that is based on econometric methods. Correct Option: B Explanation: Qualitative forecast is an estimation methodology which uses expert judgment, rather than numerical analysis. It predicts the direction, but not the magnitude of change in variable. Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank? 1.$12 min$2.$15 min$3.$25 min$4.$50 min$Correct Option: A Explanation:$\displaystyle \frac{1}{20} + \frac{1}{30} = \frac{1}{x}\displaystyle \frac{5}{60} = \frac{1}{x}     \Rightarrow 12 min\$

The first step in time-series analysis is to

1. perform preliminary regression calculations.

2. calculate a moving average.

3. plot the data on a graph.

4. identify relevant correlated variables.

Correct Option: C
Explanation:

The first step in time series analysis is to plot the data on a graph.

In moving average method, we cannot find the trend values of some:

1. Middle periods

2. End periods

3. Starting periods

4. Between extreme periods

Correct Option: D
Explanation:

In moving average method, we cannot find the trend value of some:between extreme periods.

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