Android based layout to have four buttons spread in a table on the bottom of the screen

layout.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="net.attwoodthomas.yourplanner.app.MainActivity">


    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="My Timetable"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Week"
        android:id="@+id/textView2"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <RadioGroup
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView2"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:orientation="horizontal"
        android:id="@+id/radioGroup">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Week A"
            android:id="@+id/radioButton"
            android:layout_weight="1.0"
            android:checked="true"/>

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Week B"
            android:id="@+id/radioButton2"
            android:layout_weight="1.0"/>
    </RadioGroup>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Day"
        android:id="@+id/textView3"
        android:layout_below="@+id/radioGroup"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <RadioGroup
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView3"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:id="@+id/radioGroup2">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Monday"
            android:id="@+id/radioButton3"
            android:checked="true"/>

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tuesday"
            android:id="@+id/radioButton4"
            android:checked="false" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Wednesday"
            android:id="@+id/radioButton5"
            android:checked="false" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Thursday"
            android:id="@+id/radioButton6"
            android:checked="false" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Friday"
            android:id="@+id/radioButton7"
            android:checked="false" />

    </RadioGroup>
    </LinearLayout>

    <RelativeLayout
        android:id="@+id/buttonsContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <LinearLayout
                android:id="@+id/firstRow"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <Button
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="Check Timetable"
                    android:id="@+id/button"/>

                <Button
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="Check Homework"
                    android:id="@+id/button3"
                    android:layout_above="@+id/button4"
                    android:layout_toRightOf="@+id/button2"/>

            </LinearLayout>

            <LinearLayout
                android:id="@+id/secondRow"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
                <Button
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="Update Timetable"
                    android:id="@+id/button2"/>

                <Button
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:text="Add Homework"
                    android:id="@+id/button4"/>
            </LinearLayout>

        </LinearLayout>

    </RelativeLayout>

</RelativeLayout>