Question 1 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d171f59b460d7261f44b.jpg' />
A recent survey found that the ages of workers in a factory is distributed as shown in the figure above. If a person is selected at random, find the probability that the person is under 60 but over 39 years.
Question 2 :
The median of the data 78, 56, 22, 34, 45, 54, 39, 68, 54, 84 is
Question 3 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d15cf59b460d7261f42c.jpg' />
80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of a frequency table given above. The probability that bulbs selected randomly from the lot has life less than 900 hours is :
Question 4 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d17bf59b460d7261f459.jpg' />
The mean of the following distribution shown in the above image is 50. Find the value of a.
Question 5 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d17af59b460d7261f458.jpg' />
The mean of the following distribution shown in the above image is 50. Find the value of frequency for x=70.
Question 6 :
In a sample study of 642 people, it was found that 514 people have a high school certificate. If a person is selected at random, the probability that the person has a high school certificate is :
Question 7 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d161f59b460d7261f433.jpg' />
A continuous grouped frequency distribution can be prepared from the following data shown in the above image. Find the size of class intervals.
Question 8 :
The class marks of a continuous distribution are : 1.04, 1.14, 1.24, 1.34, 1.44, 1.54 and 1.64. Is it correct to say that the last interval will be 1.55 - 1.73?
Question 9 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d16ff59b460d7261f447.jpg' />
Over the past 200 working days, the number of defective parts produced by a machine is given in the table shown above. Determine the probability that tomorrow’s output will have no defective part.
Question 10 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d15bf59b460d7261f42b.jpg' />
Two coins are tossed 1000 times and the outcomes are recorded as shown in the above figure. Based on this information, the probability for at most one head is:
Question 11 :
The width of each of five continuous classes in a frequency distribution is 5 and the lower class-limit of the lowest class is 10. The upper class-limit of the highest class is:
Question 12 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d162f59b460d7261f435.jpg' />
The given frequency distribution in the above image is converted into a continuous grouped frequency distribution. In which intervals would 153.5 be included?
Question 14 :
If each observation of the data is increased by 5, then their mean is:
Question 15 :
In a diagnostic test in mathematics given to students, the following marks (out of 100) are recorded : 46, 52, 48, 11, 41, 62, 54, 53, 96, 40, 98, 44. Which ‘average’ will be a good representative of the above data?
Question 16 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d173f59b460d7261f44e.jpg' />
A recent survey found that the ages of workers in a factory is distributed as shown in the figure above. If a person is selected at random, find the probability that the person is under 40 years.
Question 17 :
The mean of the data : 2, 8, 6, 5, 4, 5, 6, 3, 6, 4, 9, 1, 5, 6, 5 is given to be 5. Based on this information, is it correct to say that the mean of the data: 10, 12, 10, 2, 18, 8, 12, 6, 12, 10, 8, 10, 12, 16, 4 is 10?
Question 18 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d173f59b460d7261f44d.jpg' />
A recent survey found that the ages of workers in a factory is distributed as shown in the figure above. If a person is selected at random, find the probability that the person is 40 years or more.
Question 19 :
In a survey of 364 children aged 19-36 months, it was found that 91 liked to eat potato chips. If a child is selected at random, the probability that he/she does not like to eat potato chips is :
Question 21 :
If $\overline{x}_1,\ \overline{x}_2,\ \overline{x}_3,\ ...,\ \overline{x}_n$ are the means of n groups with $n_1,\ n_2,\ ...,\ n_n$ number of observations respectively, then the mean $\overline {x}$ of all the groups taken together is given by :
Question 22 :
If the mean of the observations : x, x + 3, x + 5, x + 7, x + 10 is 9, the mean of the last three observations is
Question 23 :
Mode of the data 15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15 is:
Question 24 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d166f59b460d7261f43b.jpg' />
In the above given image, obtain the mean of the following distribution.
Question 25 :
Two sections of Class IX having 30 students each appeared for mathematics olympiad. The marks obtained by them are shown below: 46, 31, 74, 68, 42, 54, 14, 61, 83, 48, 37, 26, 8, 64, 57, 93, 72, 53, 59, 38, 16, 88, 75, 56, 46, 66, 45, 61, 54, 27, 27, 44, 63, 58, 43, 81, 64, 67, 36, 49, 50, 76, 38, 47, 55, 77, 62, 53, 40, 71, 60, 58, 45, 42, 34, 46, 40, 59, 42, 29. Find the number of students who secured more than 49 marks.
Question 26 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d163f59b460d7261f436.jpg' />
The given frequency distribution in the above image is converted into a continuous grouped frequency distribution. In which intervals would 157.5 be included?
Question 27 :
A class consists of 50 students out of which 30 are girls. The mean of marks scored by girls in a test is 73 (out of 100) and that of boys is 71. Determine the mean score of the whole class.
Question 28 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d170f59b460d7261f449.jpg' />
Over the past 200 working days, the number of defective parts produced by a machine is given in the table shown above. Determine the probability that tomorrow’s output will have not more than 5 defective parts.
Question 29 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d168f59b460d7261f43d.jpg' />
A company selected 4000 households at random and surveyed them to find out a relationship between income level and the number of television sets in a home. The information so obtained is listed in the following table shown above. Find the probability of a household earning Rs 10000 – Rs 14999 per year and having exactly one television.
Question 30 :
State true or false: The observation that occurs most frequently, i.e., the observation with maximum frequency is called mode.
Question 31 :
In a histogram, the areas of the rectangles are proportional to the frequencies. Can we say that the lengths of the rectangles are also proportional to the frequencies?
Question 32 :
If $\overline {x}$ is the mean of $x_1,\ x_2,\ ...,\ x_n$ , then for a ≠ 0, the mean of, $ax_1,\ ax_2,\ ...,\ ax_n,\frac{x_1}{a},\ \frac{x_2}{a},\ ...,\ \frac{x_n}{a}$ is:
Question 33 :
A football player scored the following number of goals in the 10 matches : 1, 3, 2, 5, 8, 6, 1, 4, 7, 9. Since the number of matches is 10 (an even number), therefore, $the\ median\ =\ \frac{\left(5th\ observation\ +6th\ observation\right)}{2}=\frac{\left(8+6\right)}{2}=7$.
Is it the correct answer ?
Question 34 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d15af59b460d7261f42a.jpg' />
In a medical examination of students of a class, the following blood groups are recorded in the above table shown. A student is selected at random from the class. The probability that he/she has blood group B, is :
Question 36 :
State true or false: Mode of ungrouped data can be determined by observation/ inspection.
Question 37 :
If $\overline {x}$ represents the mean of n observations $x_1,\ x_2,\ ...,\ x_n$ , then value of $\sum_{i=1}^n\left(x_i-\overline{x}\right)$ is
Question 38 :
A grouped frequency table with class intervals of equal sizes using 250-270 (270 not included in this interval) as one of the class interval is constructed for the following data: 268, 220, 368, 258, 242, 310, 272, 342, 310, 290, 300, 320, 319, 304, 402, 318, 406, 292, 354, 278, 210, 240, 330, 316, 406, 215, 258, 236. The frequency of the class 310-330 is:
Question 39 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d15ff59b460d7261f430.jpg' />
30 children were asked about the number of hours they watched TV programmes last week. The results are recorded as shown in the above table. Can we say that the number of children who watched TV for 10 or more hours a week is 22?
Question 40 :
Median of the following numbers : 4, 4, 5, 7, 6, 7, 7, 12, 3 is:
Question 41 :
Histograms of uniform width and of varying widths is a type of graphical representation of data
Question 42 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d16af59b460d7261f440.jpg' />
Two dice are thrown simultaneously 500 times. Each time the sum of two numbers appearing on their tops is noted and recorded as given in the table shown above. If the dice are thrown once more, what is the probability of getting a sum 3?
Question 43 :
A total of 25 patients admitted to a hospital are tested for levels of blood sugar, (mg/dl) and the results obtained were as follows : 87, 71, 83, 67, 85, 77, 69, 76, 65, 85, 85, 54, 70, 68, 80, 73, 78, 68, 85, 73, 81, 78, 81, 77, 75. Find mode (mg/dl) of the above data.
Question 44 :
Can the experimental probability of an event be greater than 1?
Question 45 :
State true or false: Frequency polygons is a type of graphical representation of data
Question 46 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d166f59b460d7261f43a.jpg' />
If the mean of the following data shown in the above image is 20.2, find the value of p.
Question 47 :
For drawing a frequency polygon of a continous frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abcissae are respectively :
Question 48 :
The mean marks (out of 100) of boys and girls in an examination are 70 and 73, respectively. If the mean marks of all the students in that examination is 71, find the ratio of the number of boys to the number of girls.
Question 49 :
The following observations are arranged in ascending order : 26, 29, 42, 53, x, x + 2, 70, 75, 82, 93. If the median is 65, find the value of x.
Question 50 :
The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is :
