Grade 8 / statistics 22 exercises (100% corrected)

a
048121620240481216202428PrixeneurosNombresdefamilles Afrique68%Amérique11;3%Asie13;8%Europe6;9% B1C2D3E4F5G6A71.:pins2.:chênes3.:hêtres4.:sapins5.:charmes6.:bouleaux7.:châtaigniersO ChingQuizz : 1 exercise available for Quizz assessment : 1. Reading diagrams E.2019 A crÈche welcomes 70 children, The prices paid by families for a day at crÈche vary between 4 euros and 24 euros depending on income. The histogram of prices paid by families is : 1 Complete the statistical table below : Prix d’une journée en euros [4;8[ [8;12[ [12;16[ [16;20[ [20;24[ Total Number 70 2 Determine the number of families paying less than 20 e per day (20 e excluded) . 3 Determine the number of families paying more than 12 e per day (12 e included) . E.4658 According to, in 2009, 33.4 million people were living with the HIV virus in 2008. The diagram below shows the distribution of these people by continent : Complete the table below ; numbers should be rounded to the nearest tenth of a million and angles to the nearest unit. Afrique Amériq. Asie Europe Total Pourcentage Effectif Angle These data were produced by UNESCO. Oceania has not been included in the diagram as it represents 0.2 % of people living with HIV worldwide. E.911 A forest park has 14 400 trees. The pie chart below shows the distribution of the seven vari-eties of trees planted in this park: Geometric data related to this diagram: [ AE ] and [ BF ] are two diameters of the disk ; ( CO ) and ( AE ) are perpendicular ; angle AOB measures 30 degrees ; ( OD ) is the bisector of angle COE the measure of angle FOG is equal to half the measure of angle GOA 1 Calculate the measures of the angles : BOC ; COD ; DOE ; EOF ; FOG ; GOA 2 Determine the number of trees of each variety planted in the forest park. 2. Construction of diagrams E.5639 A daycare center serves 70 children. The price of a day at the crèche varies between 4 euros and 24 euros depending on the revenue. Here is the staffing chart summarizing the amount of money the nursery receives on an open day: https://chingmath.fr chapExoCorrec/2019 sacados/2019 048121620240481216202428PrixeneurosNombresdefamilles chapExoCorrec/4658 sacados/4658 Afrique68%Amérique11;3%Asie13;8%Europe6;9% chapExoCorrec/911 sacados/911 B1C2D3E4F5G6A71.:pins2.:chênes3.:hêtres4.:sapins5.:charmes6.:bouleaux7.:châtaigniersO chapExoCorrec/5639 sacados/5639
048121620240481216202428PrixeneurosNombresdefamilles BurkinaFasoCôted’IvoireGhanaMaliSénégalTogo01234567891011(enmillions) 27o63o72o Prix [4;8[ [8;12[ [12;16[ [16;20[ [20;24[ Nombre de familles 6 16 24 20 4 In the frame below, draw the histogram associated with this headcount table : E.4659 The bar chart below represents the number of people aged under 18 ans in 6 West African coun-tries in 2008 : UNICEF is the source of this data. 1 Complete the table below according to the following in-structions : percentages will be rounded to the nearest tenth ; angles will be rounded to the nearest unit. Burk. C.I. Ghana Mali Sén. Togo Total Effectif en millions Pourcen tage Angle 2 Draw the pie chart corresponding to this data. 3. Cumulative numbers increasing E.1097 The semicircular diagram below shows the grades of the 384 pupils in all the fourth years of a school: 1 Complete the table below ; numbers will be rounded to the nearest unit and percentage frequencies will be rounded to the nearest tenth. Classe [0 ; 5[ [5 ; 10[ [10 ; 15[ [15 ; 20[ total Angles Effectif Eff. cum. croissant Eff. cum. décroissant Fréquence en % (To complete the line of ˇ effectifs ı, use the proportional-ity between the size of the angles and this) 2 Answer the following questions : a How many students got at most 10? b How many students got at least 5? c What percentage of students got at least 10? https://chingmath.fr 048121620240481216202428PrixeneurosNombresdefamilles chapExoCorrec/4659 sacados/4659 BurkinaFasoCôted’IvoireGhanaMaliSénégalTogo01234567891011(enmillions) chapExoCorrec/1097 sacados/1097 27o63o72o
Cameroun43%R.C.A.6%Congo26%Gabon18%Tchad7% 4. Average E.1992 The table below represents the French state’s investment in secondary education (expressed in billions of euros) : Année 1980 1990 2000 2006 Investissement 12.8 30.7 47.9 53.1 Determine on average what the investment was on average for secondary education. (we’ll round his results to the tenth) . (INSEE figures) E.2021 Young basketball players were mea-sured during a training course. The sizes, in cm , are as fol-lows : 165 ; 175 ; 187 ; 165 ; 170 181 ; 174 ; 184 ; 171 ; 166 178 ; 177 ; 176 ; 174 ; 176 1 Determine the mean of this statistical series. 2 How many basketball players are below average height? E.2018 The pie chart shows the 2003 indebt-edness of 5 Central African countries. It was obtained from the World Bank website. All we know is that Cameroon had a debt of 9.1 billion in 2003. Debt values will be rounded to the tenth of a billion. 1 Copy and complete the table below : Pays Camer Congo Gabon R.C.A. Chad Montant de la dette Pourcentage Angle 2 On average, how much is a CEMAC country in debt? 5. Average and equation E.6417 During the first quarter, Oumar, an eighth grader, took four assessments all graded 20 . He remembers only the last three grades : 14 ; 12 ; 8 The math teacher tells her an average 10 = 20 for the first quar-ter. Help Oumar get his first grade back this quarter. 6. Weighted average E.1099 A student in Terminale S, mathe-matics option, obtained the following baccalaureate marks : Epreuve French Math. Phy Chim SVT H-Géo LV1 EPS Note 7 15 12 8 8 9 12 Coeff. 4 9 6 6 3 3 2 Did this student get an average on this exam? (the result will be rounded to the nearest hundredth) . E.1096 In a population of 382 individuals, we recorded, for each individual, the number of sports sessions practiced per week. Sport effectué par semaine 0 1 2 3 4 Effectifs 25 143 167 37 10 Determine, how much on average an individual practices per week, rounded to the nearest tenth, a sports session. https://chingmath.fr chapExoCorrec/1992 sacados/1992 chapExoCorrec/2021 sacados/2021 chapExoCorrec/2018 sacados/2018 Cameroun43%R.C.A.6%Congo26%Gabon18%Tchad7% chapExoCorrec/6417 sacados/6417 chapExoCorrec/1099 sacados/1099 chapExoCorrec/1096 sacados/1096
ForfaitA29oForfaitB253oForfaitC78o E.2020 Basketball player Michael Jor-dan played in all 29 games played by his team this season, and scored points in all of them. Nombre de points marqués 15 19 20 21 24 25 28 29 32 34 37 42 Nombre de matches where ce nombre de points a été marqué 2 3 1 4 3 2 6 1 3 1 2 1 Give the average number of points scored by Jordan this sea-son. E.905 In a survey of 671 students in a middle school, the amount of time d (in minutes) spent by each student doing their schoolwork each day is recorded. The results have been grouped into four classes in the table below : Frequencies will be rounded to 1% Durées de work (in minutes) 0 d< 30 30 d< 60 60 d< 90 90 d< 120 TOTAL Effectifs 106 235 144 671 Fréquences en pourcentage 16 100 1 Complete this table by rounding the frequencies to 1% . 2 Replacing each class with its center, calculate the aver- age amount of time spent each day by a student complet-ing schoolwork (This time will be given rounded to the minute) E.2331 To market tomatoes, a coop-erative sizes them according to their diameter. Below is a record of the diameter of 30 tomatoes (in millimeters) . 49 - 52 - 59 - 57 - 51 - 55 - 50 - 56 49 - 48 - 58 - 49 - 52 - 51 - 53 - 56 49 - 56 - 55 - 50 - 52 - 56 - 57 - 54 53 - 49 - 51 - 55 - 56 - 59 1 Reproduce and complete the following table : Diameters [48 ; 51[ [51 ; 54[ [54 ; 57[ [57 ; 60[ Effectif 8 Centre des classes 52.5 2 a From this table of numbers, check that the average diameter of a tomato is 54 mm , rounded to the unit. b Determine the volume, in mm 3 , of a medium-diameter tomato, modeled as a ball. Round to the nearest unit. Reminder : the volume of a ball of radius R is 4 3 · ı · R 3 Indication : we’ll use ı ≈ 3.1416 7. Weighted average and pie chart E.4677 A study was conducted at a ski re-sort of packages sold in 1 weeks ; this resort sold 2182 day passes during this study of the following three package types : Package A: it only gives access to the green run for chil-dren in training. Its price is 7 e per day. Package B : at 12 e , this package gives access to all the slopes in the resort. Package C : allowing access to neighboring resorts, this package costs 15 e . Here is the diagram representing the sale of these different packages : 1 Copy and complete the table below : Forfait A B C Angle Effectif Numbers will be rounded to the nearest whole number. 2 Determine the average price of a package purchased dur-ing this week rounded to the nearest hundredth of a euro. 8. Median of a statistical series https://chingmath.fr chapExoCorrec/2020 sacados/2020 Amerique du sud - Novembre 2003 - 3 points chapExoCorrec/905 sacados/905 chapExoCorrec/2331 sacados/2331 France 2008 chapExoCorrec/4677 sacados/4677 ForfaitA29oForfaitB253oForfaitC78o
012345678910012345 E.605 Here are the marks of four groups of students in the brevet blanc : Group 1: 5 ; 6 ; 8 ; 10 ; 12 ; 12 ; 13 ; 14 Group 2: 6 ; 8 ; 8 ; 8 ; 9 ; 12 ; 14 ; 15 Group 3: 8 ; 8.5 ; 8.5 ; 9 ; 11 ; 11 ; 12 ; 12 1 Complete the boxes for the various indicators below : Groupe 1 Group 2 Group 3 Moyenne Médiane 2 These three groups have the same mean. Based on the median values, qualitatively compare these three groups. E.901 We measured, during a train-ing course , young basketball players. The sizes, in cm , are as follows : 165 - 175 - 187 - 165 - 170 181 - 174 - 184 - 171 - 166 178 - 177 - 176 - 174 - 176 1 Calculate the average height of these basketball players. 2 What is the median height of these athletes? Justify. E.912 Mrs A and Mr B are both math teachers and both have a Troisième class with 20 pupils. They compare the marks obtained by their students on the last common homework assignment : Grades awarded by Grades awarded by Mrs A Mr B 7 - 8 - 12 - 12 - 18 - 5 - 11 8 - 8 - 9 - 12 - 11 - 8 - 13 18 - 9 - 20 - 6 - 16 - 6 - 18 10 - 12 - 8 - 10 - 14 - 12 - 11 7 - 15 - 6 - 3 - 8 - 5 14 - 9 - 15 - 7 - 9 - 10 1 Construct, on the copy and on the same drawing, the bar charts representing the two series of notes. (Use two colors) 2 Calculate the average of each series. 3 Determine a median for each series. 4 Compare these two classes. 9. Median of a staffing table E.904 Here’s a bar chart of the marks for a test graded out of 5 for a class of 25 pupils. 1 Reproduce and complete the following table of notes. 2 Calculate the average grade for the class. 3 What is the median of the class grades? 4 Calculate the frequency of grades less than or equal to 3 points out of 5. Table to complete : Note Effectif Effectif cumulé croissant https://chingmath.fr chapExoCorrec/605 sacados/605 chapExoCorrec/901 sacados/901 ?? - 2003 chapExoCorrec/912 sacados/912 chapExoCorrec/904 sacados/904 Nice, Aix-Marseille, corse, Montpellier, Toulouse - Juin 2005 012345678910012345
Nombre de personnes51015202511ans12ans13ans14ans15ans16ans PaysAPaysBPaysCPaysDPaysEPaysF00100200300400500600Quantitédenourrituregaspilléeenkgparhabitanten2010 1234ABCDPaysXPaysYPaysZ34521213510,99,446,63760500Quantitédenourrituresparhabitanten2010(enkg)Nombred’habitantsen2010(enmillions)Quantitétotalenourrituregaspillés(entonnes) E.902 The bar chart below shows the ages of young athletes taking part in a judo course. 1 How many young people are taking part in the course? 2 Copy and complete the table below. (Frequencies will be given to the nearest 0.1%) Age Effectifs Frequencies en % 3 What is the average age of the participants in this course? 4 What is the median age of the participants? 10. Unclassified exercises E.8946 The chart below represents, for six countries, the amount of food wasted (in kg ) per capita in 2010 . 1 Approximate the amount of food wasted by one person in the country D in 2010 . 2 Can we say that the food waste of a person in the coun-try F is approximately one-fifth of the food waste of a person in the country A ? 3 We want to report the amount of food wasted for other countries. So we make the table below using a spread-sheet. (recall 1 ton = 1 000 kg ) a What is the total amount of food wasted by people in X country in 2010 ? b Here are three proposed formulas, copy the one we en-tered in cell D2 onto your copy before stretching it to D4 . Proposal 1 Proposition 2 Proposition 3 =B2 × C2 × 1 000 000 =B2 × C2 =B2 × C2 × 1 000 https://chingmath.fr chapExoCorrec/902 sacados/902 ?? - 2003 Nombre de personnes51015202511ans12ans13ans14ans15ans16ans chapExoCorrec/8946 sacados/8946 PaysAPaysBPaysCPaysDPaysEPaysF00100200300400500600Quantitédenourrituregaspilléeenkgparhabitanten2010 1234ABCDPaysXPaysYPaysZ34521213510,99,446,63760500Quantitédenourrituresparhabitanten2010(enkg)Nombred’habitantsen2010(enmillions)Quantitétotalenourrituregaspillés(entonnes)