**জাতীয় বিশ্ববিদ্যালয়**

**ব্যবসায় পরিসংখ্যান**

**ক- বিভাগ**

**Brif Questions & Solution.**

**1. what is Statistics? **

** Ans:** Statistics is the science of decision making in the field of uncertainty.

**2. who is the father of modern statistics?**

**Ans:** R.A. Fisher.

**3. what is the origin of the word Statistics?**

**Ans:** the origin of the word Statistics in status or statistic.

**4. what is Business Statistics?/ What is mean by Business Statistics?**

**Ans:** Business Statistics is a science Assisting us to make business decision under uncertainties based on some numerical and measurable scale.

**5. What is variable?**

**Ans:** the characteristic which varies over the units is called variable.

**6. what is data?**

**Ans:** Data are the collection of row facts and figures from any sets of inquiry for the purpose from any sets of inquiry for the purpose of statistical analysis.

**7. What is statistical data?**

**Ans**: A collection of any number of related observation on one or more variables is called statistical data.

**8. what are sources of data?**

**Ans:** Data can be collected from three sources:

1. Primary Source.

2. Secondary Source

3. Internal Source.

**9. Write the definition of continuous variable with examples.**

**Ans:** A continuous variable is one that can take on any value within given range.

**10. what is ogive curve?**

**Ans:** Ogive is a graph of cumulative frequency distribution.

**11. what is Stem and leaf diagram?**

**Ans:** Stem and leaf Display is a statistical technique to present a set of data.

**12. What is frequency polygon?**

**Ans:** A frequency polygon expresses distribution of data by meab of a single line determined by the midpoints of classes.

**13. what is pie chart?**

**Ans:** A pie chart presents the data in the form of a circle.

**14. what is data?**

**Ans:**A collection of any number of related observations of none or more variables are called data.

**15. what is raw data?**

**Ans:**Information before it is arranged or analyzed by statistical methods are raw data.

**16. What is classification?**

**Ans:**classification is the process of arranging data as collected by proper investigation in some groups or class in relation with definite. characteristics grouping of related facts into classes.

**17. what is bar diagram?**

**Ans:**Bar diagrams are the most common type of diagrams used in practice. A bar is a thick line whose width is shown merely for attention.

**18. what is Scatter diagram?**

**Ans:**A graph of points on a rectangular grid the X and Y coordinates of each point corresponded to the two measurements made on some particular sample element and the pattern of points illustrates the relationship between the two variables.

**19. What is Sample?**

**Ans:**A collection of some but not all of the elements of the population under study used to describe the population.

**20. What is data array?**

**Ans:**An organized display of data that shows the number of observations from the data set that falls into each of a set of mutually exclusive and collectively exhaustive classes is frequency distribution.

**21. What is frequency density?**

**Ans:**frequency density is the percentage of observation fall within each class in respect of their class width.

**22. what is population?**

**Ans:**A collection of all the elements we are studying and about which we are trying to draw exclusions.

**23. what is central tendency?**

**Ans:**Central tendency is a typical value of a data set around

**24.Define Quadrilles.**

**Ans:**the quadrilles that divide the data into 4 equal parts.

**25. what is the relationship among AM, GM & HM?**

**Ans:**AM≥GM≥HM

**26. What is Harmonic Mean.**

**Ans:**Harmonic mean is the ratio between the number of items and the sum of reciprocals of items.

**27. What is Average ?**

**Ans:**Average is an attempt to find one single figure to describe whole of figures.

**28. What is frequency Distribution?**

**Ans:**An organized display of data that shows the number of observations from the data set that falls info each of a set of mutually exclusive and collectively exhaustive classes.

**29. What is Equal class interval?**

**Ans:**the distribution which with of the each class is equal is called equal class interval. for example 10-20 , 20-30, 30-40 and 50-60.

**30. What is Stem and leaf display?**

**Ans:**one technique that is used to display quantitative information in a condensed form is the stem and leaf display.

**31. What is Dispersion?**

**Ans:**the distance of different values from the central value is called dispersion.

**32. What do you mean measures of dispersion.**

**Ans:**the measures of dispersion are called averages of second order.

**33. How many types of measure of dispersion?**

**Ans:**Two types of measure of dispersion (1) Absolute measure (2) relative measure.

**34. The difference between the first and third quartertile is called the?**

**Ans:**Inter Quartile range.

**35. What is the range of 0, 2?**

**Ans:**Range = highest value- Lowest Value=0-2=-2

**36. What is the mode of 4, 6, 8, 10, 6, and 12?**

**Ans:**6

**37. What is**

**absolute**

**measure?**

**Ans:**When dispersion is measured in original units then it is known as absolute measure of dispersion.

**38. what is mean deviation?**

**Ans:**Mean deviation is the arithmetic mean of the deviation of series computed from any measures of central tendency.

**39. find the mean if co-efficient of variance =15% and variance=4?**

**Ans:**we know

**40. mention the relationship among mean median and mode in case of positively skewed distribution.**

**Ans:**In case of positive skewed distribution the relationship among mean median and mode are X

**41. what**

**is Box plot?**

**Ans:**Box plot is the graphical presentation of five number summaries.

**42. What is Random variable?**

**Ans:**Random variable is a variable whose values are determined by chance.

**43. What is skewness ?**

**Ans:**SKewness is the degree of a symmetry or departure from symmetry of a distribution.

**44. What is null hypothesis?**

**Ans:**The hypothesis about a population parameter we wish to test is called a null hypothesis.

**45. What do you mean by**

**Ans:**

**46. Define co-efficient of correlation.**

**Ans:**Co-efficient of correlation is the measure of the strength of the linear relationship between two variables.

**47. What is mean by r=+1, r=-1 and r= 0?**

**Ans:**the value of r=+1, Means the prefect positive correlation. the value of r=-1, means called perfect negative correlation.

**48. in case of unequal rank write the formula of rank correlation.**

**Ans:**Rank correlation 1-

**49. what is regression line?**

**Ans:**A line fitted to set data points to estimate the relationship between two variables.

**50. what is regression Analysis?**

**Ans:**Regression Analysis is a mathematical measure of the average relationship between two or more variables in terms of original units of the data.

**51. what is dependent variables?**

**Ans:**The variables we are trying to predict in regression analysis is called dependent variable.

**52. what is index number?**

**Ans:**index number may be defined as the ratio that measures how much a variable over time

**53. How many types of index number?**

**Ans:**Index number are 3 kinds. (1) price index (2) quantity index (3) Variable index.

**54. What is family budget method.**

**Ans:**Which the consumer price index is computed on the family budgets of large number of people, is called family budget method.

**55. under what condition time reversal test and factor reversal test is satisfied?**

**Ans:**Time Reversal Test is satisfied when opn×npo=1

**56. Write down the components of time series.**

**Ans:**The components of time series are (1) Trend (2) Seasonal variation (3) cyclical variation (4) Irregular variation.

**57. What is meant by HO and HA?**

**Ans:**Ho Means null hypothesis Ha means Alternative Hypothesis.

vai aikhane to sudhu part-A ache..part-B & part-C kothay???

part B and part C kothay??

nice