Grade 7 / statistics 25 exercises (100% corrected)

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Nombred’élèves(dizainedemilliers)1020304050En avanceA l’âgeEn retardd’un anEn retardde 2 anset plus 1. Workforce E.5632 Adrian surveys the members of his entourage to find out how many times everyone has been to the movies in the past month. Here are the results : 2 ; 3 ; 1 ; 0 ; 2 ; 4 ; 2 ; 1 ; 0 1 ; 1 ; 0 ; 2 ; 0 ; 1 ; 3 ; 1 1 Give the total number of people in this study. 2 Give the headcount of people who went to the movies exactly twice in the past month. 2. Frequencies E.5634 The bar chart below shows the num-ber of students enrolled in the schools and the difference in their age in relation to their level of schooling at the beginning of the school year 2003: 1 What is the number of students ˇ at age ı? 2 a Determine the total number of students enrolled dur-ing the year 2003 . b Deduct the class frequency of students ˇ at age ı rounded to the nearest thousandth. 3. Classes and staff E.5635 Here are the heights, expressed in meters, of students in a fifth grade class : 1.42 ; 1.50 ; 1.38 ; 1.56 ; 1.62 ; 1.61 1.72 ; 1.65 ; 1.42 ; 1.45 ; 1.54 ; 1.32 1.44 ; 1.56 ; 1.58 ; 1.45 ; 1.73 ; 1.74 1.62 ; 1.46 ; 1.54 ; 1.52 ; 1.71 ; 1.73 1 Give the total size of the study population. 2 Complete the headcount table below : Taille (en m ) [1.3 ; 1.4[ [1.4 ; 1.5[ [1.5 ; 1.6[ [1.6 ; 1.7[ [1.7 ; 1.8[ Number 4. Classes and frequencies E.5633 Here are the grades of students in a fifth grade class : 12 ; 16 ; 8 ; 11 ; 10 ; 14 ; 7 ; 5 15 ; 12 ; 12 ; 8 ; 10 ; 12 ; 15 ; 6 7 ; 13 ; 14 1 Give the total size of the study population. 2 a Give the class size ˇ the student’s grade is between 10 inclusive and 12 exclus ı. b Complete the following headcount table by arranging the values in the table : Note [4;6[ [6;8[ [8;10[ [10;12[ [12;14[ [14;16[ [16;18[ Headcount 3 Give the frequency, rounded to the nearest thousandth, corresponding to students who had between 10 inclusive and 12 exclusive. https://chingmath.fr chapExoCorrec/5632 sacados/5632 chapExoCorrec/5634 sacados/5634 Nombred’élèves(dizainedemilliers)1020304050En avanceA l’âgeEn retardd’un anEn retardde 2 anset plus chapExoCorrec/5635 sacados/5635 chapExoCorrec/5633 sacados/5633
8910111213141501234567NotesE∑ectifs 2028364452600510152025303540 5. Bar graph: reading E.7913 The bar graph below shows the dis-tribution of scores on a math test by students in a class of 3 e . 1 How many students are in this class? 2 a How many students got 12 on this test? b How many students got at least 12 on this test? 3 Which grade groups the most students? 6. Bar graphs: constructions E.1563 Here are some data published by the CIA in 2004, on the number of Internet users in a number of European countries : Allemagne France Pologne Royaume Uni Nombres d’utilisateurs (in millions) 82 60 40 60 Using the scale ˇ 1 cm =10 million utilisateurs ı, construct the bar chart representing this statistical study. E.906 In a company, the age of 125 employees has been studied. The results of this study are given in the following table : Age [20; 28[ [28; 36[ [36; 44[ [44; 52[ [52; 60[ Total Nombre de salariés n i 15 35 40 10 Fréquences en % 1 Complete the table above. 2 Draw the histogram of the numbers using the grid below. 3 a How many employees are under 44 years old? b How many employees are 36 years old and over? c What percentage of employees are between 52 years old and 60 years old? 7. Cartesian graph: reading E.7914 On the graph below, we have plotted Mathieu’s math scores throughout the school year. https://chingmath.fr chapExoCorrec/7913 sacados/7913 8910111213141501234567NotesE∑ectifs chapExoCorrec/1563 sacados/1563 chapExoCorrec/906 sacados/906 Groupe Ouest Juin 2003 12 points 2028364452600510152025303540 chapExoCorrec/7914 sacados/7914
Contrôle numéro23456789101112INote2468101214161820JO 27Nov.0 06=083500 1 On which homework assignment did Mathieu get his best grade? 2 How many grades did Mathieu get that were strictly be-low average? 8. Cartesian graph: constructions E.2812 Mathias has compiled a table of notes : Date 27 Nov. 28 Nov 1 Déc 4 Déc 6 Déc Note 10 14 9 12 8 He would like to draw up a Cartesian graph using the refer-ence frame below : To do this, use : the x-axis to represent all days from 27 November to 6 December. the y-axis should represent all values from 0 to 16 . E.2273 The value of the CAC40 stock mar-ket index on the Paris stock exchange is recorded every first of the month. Here is the reading for the last 6 months : Date Juin 08 Juillet 08 Août 08 Sept. 08 Oct. 08 Nov. 08 Valeur 4750 6500 5000 4250 3500 3750 We wish to graph the data in this table in the frame below : To do this : We start the ordinate scale from the value 3 500 and adapt the scale to make maximum use of this axis. The x-axis starts at 06 = 08 and should represent all months up to November 2008. https://chingmath.fr Contrôle numéro23456789101112INote2468101214161820JO chapExoCorrec/2812 sacados/2812 27Nov.0 chapExoCorrec/2273 sacados/2273 06=083500
0 E.3900 The size of a child over the ages was noted : Age 0 years 2 years 4 ans 8 ans 12 ans 14 ans 16 ans Taille (en cm) 40 60 90 120 130 140 160 Construct the Cartesian graph associated with this table in the reference frame below, observing the scale : On the x-axis: 1 cm represents 2 years ; On the y-axis: 1 cm represents 20 cm . E.3869 A maths teacher gives one test a month to his sixth-form class. In the table below, he plots the number of pupils who obtained the average at each test : Month Sept. Oct. Nov. Déc. Jan. Fév. Mars Mai Juin Nombre d’élèves 18 14 16 10 8 12 14 16 14 Draw the Cartesian graph associated with this table using the following scale : On the x-axis: 1 cm represents 1 months ; On the y-axis: 1 cm represents 2 points. E.3740 A chemist observes the temperature of one of his experiments for 6 h ; here is the summary table of his observations : Temps d’observation (en h ) 0 1 2 3 4 5 6 Température (en o C ) 17 12 10 11 13.5 15 17 Draw the Cartesian graph representing these data using the following scales : on the x-axis: 1 h =2 cm ; on the y-axis: 1 o C =1 cm E.2223 Here are the temperatures recorded in Montpellier on a particular day in October Heure 0 2 4 6 8 10 Température (en o C ) 17 15 14 16 17 18 Heure 12 14 16 18 20 22 Température (en o C ) 20 21 23 22 20 18 1 What temperature was recorded at 6 h ? at 18 h ? 2 At what times was a temperature of 20 o C recorded? 3 Represent the data provided by the table below in a Cartesian graph : where : the x-axis must represent all values from 0 h to 24 h . the y-axis must represent all values from 0 o to 24 o . 9. Circular diagrams: reading E.2224 All sixth form classes met to elect their representatives to the school council. Four students were candidates, and here are the results : Candidat Luc Andréa Lucie Alphonse Nombre de voix 15 % 50 % 25 % 10 % Here is the pie chart representation of this table, but all indi-cations have been removed. https://chingmath.fr chapExoCorrec/3900 sacados/3900 0 chapExoCorrec/3869 sacados/3869 chapExoCorrec/3740 sacados/3740 chapExoCorrec/2223 sacados/2223 chapExoCorrec/2224 sacados/2224
BleuJauneVert 27o63o72o18o 048121620240481216202428PrixeneurosNombresdefamilles Complete the pie chart with the information in table (name and percentage of vote obtained) . E.5638 In a survey, participants were asked to choose their favorite color from blue, green, and yellow. These results were translated into the semi-circular diagram below : Is there a color that won more than 50 % of the votes? E.5637 The semicircular diagram below shows the first quarter averages in mathematics of fifth graders at a middle school. The students were sorted into five classes. Next to each class, the measurement in degrees of the angular sector representing it is indicated. 1 Determine the percentage frequency of students who had between 10 inclusive and 15 excluded from the average. 2 Knowing that this school has 127 fifth graders, determine the number of students who had an average between 10 included and 15 excluded. 10. Pie charts: constructions E.913 Here are the results of a survey car-ried out in a class of ninth graders on the means of transport they use to get to school. Voiture Bus A foot Booster Total Fréquence 45 % 25 % 20 % Angle 1 Copy and complete the following table 2 Construct a 3 cm -radius pie chart representing this sta-tistical series. E.1462 A crèche welcomes 70 children, The prices paid by families for a day at crèche vary between 4 eu-ros and 24 euros depending on income. The histogram of prices paid by families is shown below : We’ll give the default approximate value to unity for angle and frequency measurements. 1 Copy and complete the statistical table below : Prix d’une journée (en euro) [4;8[ [8;12[ [12;16[ [16;20[ [20;24[ Effectifs Fréquences en pourcentage Angles Percentage frequencies are rounded to the nearest tenth and angles to the nearest degree. 2 Construct the pie chart corresponding to the headcount table. 11. Average of a statistical series E.4674 The table below shows the number of rainy days per year: Année 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Nombres de jours de pluie 57 81 77 77 82 86 90 98 97 76 https://chingmath.fr chapExoCorrec/5638 sacados/5638 BleuJauneVert chapExoCorrec/5637 sacados/5637 27o63o72o18o chapExoCorrec/913 sacados/913 chapExoCorrec/1462 sacados/1462 048121620240481216202428PrixeneurosNombresdefamilles chapExoCorrec/4674 sacados/4674
Determine over these 10 years, the average number of rainy days per year. E.5477 People are asked 10 about the num-ber of times they have been to a museum in the past month. Here are their responses : 2 ; 0 ; 4 ; 1 ; 0 ; 2 ; 3 ; 2 ; 1 ; 2 1 Give the percentage frequency of ˇ people who have made two visits to a museum in the past month ı. 2 Determine the average number of times this group visited a museum in the past month. E.1991 The table below shows the number of people, in thousands, in each of the CEMAC countries in 2005: Cameroun Centrafrique Congo Gabon G. équat. Tchad 16 322 4 038 3 999 1 384 650 9 749 (according to the Cameroonian Institute of Statistics) 1 What is the total population of CEMAC? 2 Give the percentage, to the nearest tenth, of each coun-try’s population relative to the whole of CEMAC. 3 Calculate the average population per country. E.4660 1 The tables below represent the average maximum tem-peratures in 2008 for each month in Lomé: Mois Janvier Février Mars Avril Mai Juin Température (en o C ) 32.5 33.8 33.1 33.8 32.9 30.5 Mois Juillet Août Sept. Oct. Nov. Dec. Température (en o C ) 29.6 29.1 29.0 31.9 33.4 33.0 Determine, to the nearest tenth of a degree, the average maximum in Lomé in 2008 . 2 The tables below represent the average minimum temper-atures in 2008 for each month in Lomé: Mois Janvier Février Mars Avril Mai Juin Température (en o C ) 21.4 25.3 26.2 25.7 24.7 23.9 Mois Juillet Août Sept. Oct. Nov. Dec. Température (en o C ) 24.4 23.9 24.1 24.7 25.5 25.2 Which month has the most amplitude between the aver-age high and average low in 2008? E.3764 At a rental store, the man-ager counted the number of DV D rented during a week and obtained the results shown in the following table : Mon. Tue. Wed. Thu. Fri. Sat. Sun. Number of DV D rented 19 15 16 14 20 74 52 1 What is the total number of DV D rented over the entire week? 2 Calculate the average number of DV D rented per day during this week. 3 Calculate the percentage of DV D rented during the week-end (Saturday and Sunday) compared to the entire week. 12. Unclassified exercises E.1432 A statistician has classified a city’s pop-ulation according to their blood groups. He also calculated the angles needed to represent each of these groups in a pie chart : Blood types O A B AB Effectifs 2380 1921 1394 Angles représentés 140 113 82 Unfortunately, the data corresponding to individuals with blood group AB has been lost. 1 Explain how to obtain the missing data. Then complete the table. 2 Make the associated pie chart. https://chingmath.fr chapExoCorrec/5477 sacados/5477 chapExoCorrec/1991 sacados/1991 chapExoCorrec/4660 sacados/4660 chapExoCorrec/3764 sacados/3764 chapExoCorrec/1432 sacados/1432