Bài 1: Kết quả đo chiều cao (cm) của đội văn nghệ của một trường THPT được ghi lại như
sau:
169 168 174 172 166 173 170 168 168
167 175 165 168 176 170 173 169 175
167 172 167 165 172 172 175 168 166
a) Hãy lập bảng phân phối ghép lớp: (165-167); (168-170); ...; (174-176).
b) Tính số trung bình cộng.
Bài 4. Kết quả đo chiều cao (cm) của một đội múa của một câu lạc bộ như sau :
169 168 174 172 166 173 170 168 168
167 175 165 168 176 170 173 169 175
167 172 167 165 172 172 175 168 166
a) Hãy lập bảng phân phối ghép lớp : (165 – 167) ; (168 –170) ; (171–173);(174 –176).
b) Tính số trung bình cộng theo bảng phân phối ghép lớp.
Mẫu số liệu sau cho biết chiều cao (đơn vị cm) của các bạn trong tổ:
163 159 172 167 165 168 170 161
Tính khoảng biến thiên của mẫu số liệu này.
Số lớn nhất là 172, số nhỏ nhất là 159
R = 172 - 159 = 13
Tính nhanh
164+165+166+167+168+.........+1000=
Áp dụng công thức tính dãy số ta có :
\(164+165+...+1000=\frac{\left[\left(1000-164\right):1+1\right].\left(1000+164\right)}{2}=\frac{837.1164}{2}=487134\)
\(164+165+166+...+1000\)
\(=\frac{\left(\left\{1000+164\right\}.\left[1000-164\right]:1+1\right)}{2}\)
\(=\frac{974268}{2}=487134\)
164+165+166+167+168+...+1000
=[(164+1000)x(1000-164):1+1]:2
=[1164x836]:2
=973104:2
=486552
Giúp mình bài tập với ạ
Câu 1 Chiều cao của một tổ tiếp viên hàng không được ghi lại lần lượt là
160 170 165 167 172 166 168
a.Tìm giá trị trung bình
b.Tìm tứ phân vị của mẫu số liệu
c.Tìm độ lệch chuẩn và phương sai của mẫu số liệu
Câu 2 Cho hình bình hành ABCD
a.Tính Vectơ AB+Vectơ CD+Vectơ BC+Vectơ DA=?
b.Với điểm M bất kì chứng minh rằng Vectơ MA+Vectơ MC=Vectơ MD+Vectơ MB
Câu 3 cho parabol(P):y=ax2+bx+c,(a≠ 0) đi qua điểm A(2;3) và có đỉnh I(1;2) xác định P
Câu 3:
Theo đề, ta có;
\(\left\{{}\begin{matrix}4a+2b+c=3\\-\dfrac{b}{2a}=1\\-\dfrac{b^2-4ac}{4a}=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\b^2-4ac=-8a\\4a+2b+c=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\4a^2-4ac=-8a\\4a+2b+c=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\4a\left(a-c\right)=4a\cdot\left(-2\right)\\4a+2b+c=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\c=a+2\\4a-4a+a+2=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=1\\b=-2\\c=3\end{matrix}\right.\)
Câu 3:
Theo đề, ta có;
\(\left\{{}\begin{matrix}4a+2b+c=3\\-\dfrac{b}{2a}=1\\-\dfrac{b^2-4ac}{4a}=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\b^2-4ac=-8a\\4a+2b+c=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\4a^2-4ac=-8a\\4a+2b+c=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\4a\left(a-c\right)=4a\cdot\left(-2\right)\\4a+2b+c=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}b=-2a\\c=a+2\\4a-4a+a+2=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=1\\b=-2\\c=3\end{matrix}\right.\)
164. It’s a six–hour drive from London to Edinburgh.
It takes _________________________________________________________________
165. It’s ages since Alan visited his parents.
Alan ___________________________________________________________________
166. Mr. Will lost his job because he was late every day.
If _____________________________________________________________________
167. The police made the youth empty his pocket.
The youth ______________________________________________________________
168. Lawrence hasn’t seen his sister since she left for Japan.
Lawrence last ___________________________________________________________
169. John is fat because he eats so many chips.
If _____________________________________________________________________
170. If Joe doesn’t change his way, he will end up in prison.
Unless _________________________________________________________________
171. Having a vacation abroad is interesting.
It’s ____________________________________________________________________
172. The water was so cold that the children could not take a swim.
The water wasn’t _________________________________________________________
173. It’s two months since I last spoke to her.
I haven’t _______________________________________________________________
164. It’s a six–hour drive from London to Edinburgh.
It takes ________six hours to drive from London to Edinburgh.____________________________________
165. It’s ages since Alan visited his parents.
Alan _______hasn't visited his parents for ages__________________________________________________
166. Mr. Will lost his job because he was late every day.
If _______Mr. Will hadn't been late every day,he wouldn't have lost his job_________________________________________
167. The police made the youth empty his pocket.
The youth _______was made empty his pocket._______________________________________________
168. Lawrence hasn’t seen his sister since she left for Japan.
Lawrence last ______saw his sister when she left for Japan.___________________________________________
169. John is fat because he eats so many chips.
If ________John didn't eat so many chips,he wouldn't be fat______________________________________________
170. If Joe doesn’t change his way, he will end up in prison.
Unless ________________Joe changes his way, he will end up in prison.___________________________________
171. Having a vacation abroad is interesting.
It’s _________interesting to have a vacation abroad___________________________________________
172. The water was so cold that the children could not take a swim.
The water wasn’t _______warm enough for the children to take a swim. _______________________________________
173. It’s two months since I last spoke to her.
I haven’t _________spoken to her for two months__________
(5/167+7/168-8/169)x(1/2+1/3-5/6)
kết quả đo chiều cao ( đơn vị:cm) của 6 bạn trong đội bóng chuyền của trường là:164; 165; 167; 170;171; 169. Chiều cao trung bình của đội bóng bằng
Chiều cao trung bình của đội bóng:
(164 + 165 + 167 + 170 + 171 + 169) : 6 ≈ 167,7 (cm)
166. “Are Tam and Hoa late for class?” Tuan asked Lan
………………………………………
167. She said to me “Can you speak Chinese?”
………………………………………
168. “Will she be here for five days?” Tam asked Thu
………………………………………
169. “Were you reading this book at 8 o’clock last Sunday?” She asked Ba
………………………………………
166. “Are Tam and Hoa late for class?” Tuan asked Lan
………………………tuan asked lan if tam and hoa were late for class………………
167. She said to me “Can you speak Chinese?”
…………………… she asked if/whether I could speak Chinese…………………
168. “Will she be here for five days?” Tam asked Thu
…………………Tam asked Thu if she would be there for 5 days……………………
169. “Were you reading this book at 8 o’clock last Sunday?” She asked Ba
………………………she asked ba if he had been reading that book at 8 o’clock the previous Sunday………………